diff --git a/Api.SeaHavenIndustries.Tests/TeamPermissionOverrideDataServiceTests.cs b/Api.SeaHavenIndustries.Tests/TeamPermissionOverrideDataServiceTests.cs
new file mode 100644
index 0000000..0f0861e
--- /dev/null
+++ b/Api.SeaHavenIndustries.Tests/TeamPermissionOverrideDataServiceTests.cs
@@ -0,0 +1,80 @@
+using Data.SeaHavenIndustries;
+using Data.SeaHavenIndustries.Enums;
+using FluentAssertions;
+using Microsoft.AspNetCore.Identity;
+using Microsoft.EntityFrameworkCore;
+using SeaHaven.DataServices.Implementation;
+using Xunit;
+
+namespace Api.SeaHavenIndustries.Tests;
+
+public sealed class TeamPermissionOverrideDataServiceTests
+{
+    [Fact]
+    public async Task GetUserAsync_ReturnsIdentityRoleAndStoredOverrides()
+    {
+        await using var context = NewContext();
+        SeedUserWithRole(context, "u1", "Dispatcher");
+        context.UserPermissionOverrides.Add(new UserPermissionOverride
+        {
+            UserId = "u1",
+            PermissionKey = "deleteSites",
+            State = UserPermissionState.Deny
+        });
+        await context.SaveChangesAsync();
+
+        var result = await new TeamPermissionOverrideDataService(context)
+            .GetUserAsync("u1", CancellationToken.None);
+
+        result.Should().NotBeNull();
+        result!.RoleName.Should().Be("Dispatcher");
+        result.Overrides["deleteSites"].Should().Be(UserPermissionState.Deny);
+    }
+
+    [Fact]
+    public async Task SetOverrideAsync_UpsertsOneCompositeKey()
+    {
+        await using var context = NewContext();
+        SeedUserWithRole(context, "u1", "Scheduler");
+        await context.SaveChangesAsync();
+        var service = new TeamPermissionOverrideDataService(context);
+
+        await service.SetOverrideAsync("u1", "deleteSites", UserPermissionState.Allow, CancellationToken.None);
+        await service.SetOverrideAsync("u1", "deleteSites", UserPermissionState.Deny, CancellationToken.None);
+
+        var rows = await context.UserPermissionOverrides.ToListAsync();
+        rows.Should().ContainSingle();
+        rows[0].State.Should().Be(UserPermissionState.Deny);
+    }
+
+    private static ApplicationDbContext NewContext()
+    {
+        var options = new DbContextOptionsBuilder<ApplicationDbContext>()
+            .UseInMemoryDatabase(Guid.NewGuid().ToString())
+            .Options;
+        return new ApplicationDbContext(options);
+    }
+
+    private static void SeedUserWithRole(ApplicationDbContext context, string userId, string roleName)
+    {
+        context.Users.Add(new ApplicationUser
+        {
+            Id = userId,
+            UserName = userId,
+            NormalizedUserName = userId.ToUpperInvariant(),
+            Email = userId + "@example.com",
+            NormalizedEmail = (userId + "@example.com").ToUpperInvariant()
+        });
+        context.Roles.Add(new IdentityRole
+        {
+            Id = "role-1",
+            Name = roleName,
+            NormalizedName = roleName.ToUpperInvariant()
+        });
+        context.UserRoles.Add(new IdentityUserRole<string>
+        {
+            UserId = userId,
+            RoleId = "role-1"
+        });
+    }
+}
diff --git a/Api.SeaHavenIndustries/Controllers/TeamPermissionController.cs b/Api.SeaHavenIndustries/Controllers/TeamPermissionController.cs
new file mode 100644
index 0000000..72704cc
--- /dev/null
+++ b/Api.SeaHavenIndustries/Controllers/TeamPermissionController.cs
@@ -0,0 +1,65 @@
+using Data.SeaHavenIndustries;
+using Data.SeaHavenIndustries.Enums;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using SeaHaven.Services.DTOs;
+using SeaHaven.Services.Interfaces;
+
+namespace Api.SeaHavenIndustries.Controllers;
+
+[Authorize]
+[ApiController]
+[Route("api/User/{userId}/Permissions")]
+public sealed class TeamPermissionController : ControllerBase
+{
+    private readonly ITeamPermissionService _permissionService;
+
+    public TeamPermissionController(ITeamPermissionService permissionService)
+    {
+        _permissionService = permissionService;
+    }
+
+    [HttpGet]
+    public async Task<IActionResult> GetProfile(
+        string userId,
+        CancellationToken cancellationToken)
+    {
+        var result = await _permissionService.GetProfileAsync(userId, User, cancellationToken);
+        return ToActionResult(result);
+    }
+
+    [HttpPut("{permissionKey}")]
+    public async Task<IActionResult> SetOverride(
+        string userId,
+        string permissionKey,
+        [FromBody] SetTeamPermissionOverrideDTO request,
+        CancellationToken cancellationToken)
+    {
+        if (!Enum.IsDefined(request.State))
+            return BadRequest(new Response { Status = "Error", Message = "Invalid permission state." });
+
+        var result = await _permissionService.SetOverrideAsync(
+            userId,
+            permissionKey,
+            request.State,
+            User,
+            cancellationToken);
+        return ToActionResult(result);
+    }
+
+    private static IActionResult ToActionResult(
+        TeamPermissionResult<TeamPermissionProfileDTO> result)
+    {
+        return result.Status switch
+        {
+            TeamPermissionResultStatus.Success => new OkObjectResult(result.Value),
+            TeamPermissionResultStatus.Forbidden => new ForbidResult(),
+            TeamPermissionResultStatus.NotFound => new NotFoundObjectResult(
+                new Response { Status = "Error", Message = "User not found." }),
+            TeamPermissionResultStatus.InvalidPermissionKey => new BadRequestObjectResult(
+                new Response { Status = "Error", Message = "Unknown permission key." }),
+            _ => new BadRequestObjectResult(
+                new Response { Status = "Error", Message = "Unable to update permissions." })
+        };
+    }
+}
diff --git a/SeaHaven.DataServices/Dto/TeamPermissionReadModels.cs b/SeaHaven.DataServices/Dto/TeamPermissionReadModels.cs
new file mode 100644
index 0000000..d90a90f
--- /dev/null
+++ b/SeaHaven.DataServices/Dto/TeamPermissionReadModels.cs
@@ -0,0 +1,11 @@
+using Data.SeaHavenIndustries.Enums;
+
+namespace SeaHaven.DataServices.Dto;
+
+public sealed class TeamPermissionUserData
+{
+    public required string UserId { get; init; }
+    public string? RoleName { get; init; }
+    public IReadOnlyDictionary<string, UserPermissionState> Overrides { get; init; }
+        = new Dictionary<string, UserPermissionState>(StringComparer.OrdinalIgnoreCase);
+}
diff --git a/SeaHaven.DataServices/Implementation/TeamPermissionOverrideDataService.cs b/SeaHaven.DataServices/Implementation/TeamPermissionOverrideDataService.cs
new file mode 100644
index 0000000..954e8a4
--- /dev/null
+++ b/SeaHaven.DataServices/Implementation/TeamPermissionOverrideDataService.cs
@@ -0,0 +1,84 @@
+using Data.SeaHavenIndustries;
+using Data.SeaHavenIndustries.Enums;
+using Microsoft.EntityFrameworkCore;
+using SeaHaven.DataServices.Dto;
+using SeaHaven.DataServices.Interfaces;
+
+namespace SeaHaven.DataServices.Implementation;
+
+public sealed class TeamPermissionOverrideDataService : ITeamPermissionOverrideDataService
+{
+    private readonly ApplicationDbContext _context;
+
+    public TeamPermissionOverrideDataService(ApplicationDbContext context)
+    {
+        _context = context;
+    }
+
+    public async Task<TeamPermissionUserData?> GetUserAsync(
+        string userId,
+        CancellationToken cancellationToken)
+    {
+        var userExists = await _context.Users
+            .AsNoTracking()
+            .AnyAsync(user => user.Id == userId, cancellationToken);
+
+        if (!userExists)
+            return null;
+
+        var roleName = await (
+            from userRole in _context.UserRoles.AsNoTracking()
+            join role in _context.Roles.AsNoTracking()
+                on userRole.RoleId equals role.Id
+            where userRole.UserId == userId
+            select role.Name)
+            .FirstOrDefaultAsync(cancellationToken);
+
+        var overrides = await _context.UserPermissionOverrides
+            .AsNoTracking()
+            .Where(permission => permission.UserId == userId)
+            .ToDictionaryAsync(
+                permission => permission.PermissionKey,
+                permission => permission.State,
+                StringComparer.OrdinalIgnoreCase,
+                cancellationToken);
+
+        return new TeamPermissionUserData
+        {
+            UserId = userId,
+            RoleName = roleName,
+            Overrides = overrides
+        };
+    }
+
+    public async Task SetOverrideAsync(
+        string userId,
+        string permissionKey,
+        UserPermissionState state,
+        CancellationToken cancellationToken)
+    {
+        var existing = await _context.UserPermissionOverrides
+            .SingleOrDefaultAsync(
+                permission => permission.UserId == userId
+                    && permission.PermissionKey == permissionKey,
+                cancellationToken);
+
+        if (existing is null)
+        {
+            await _context.UserPermissionOverrides.AddAsync(
+                new UserPermissionOverride
+                {
+                    UserId = userId,
+                    PermissionKey = permissionKey,
+                    State = state
+                },
+                cancellationToken);
+        }
+        else
+        {
+            existing.State = state;
+        }
+
+        await _context.SaveChangesAsync(cancellationToken);
+    }
+}
diff --git a/SeaHaven.DataServices/Interfaces/ITeamPermissionOverrideDataService.cs b/SeaHaven.DataServices/Interfaces/ITeamPermissionOverrideDataService.cs
new file mode 100644
index 0000000..49d57e2
--- /dev/null
+++ b/SeaHaven.DataServices/Interfaces/ITeamPermissionOverrideDataService.cs
@@ -0,0 +1,14 @@
+using Data.SeaHavenIndustries.Enums;
+using SeaHaven.DataServices.Dto;
+
+namespace SeaHaven.DataServices.Interfaces;
+
+public interface ITeamPermissionOverrideDataService
+{
+    Task<TeamPermissionUserData?> GetUserAsync(string userId, CancellationToken cancellationToken);
+    Task SetOverrideAsync(
+        string userId,
+        string permissionKey,
+        UserPermissionState state,
+        CancellationToken cancellationToken);
+}
diff --git a/SeaHaven.Services.Tests/TeamPermissionServiceTests.cs b/SeaHaven.Services.Tests/TeamPermissionServiceTests.cs
new file mode 100644
index 0000000..048c94b
--- /dev/null
+++ b/SeaHaven.Services.Tests/TeamPermissionServiceTests.cs
@@ -0,0 +1,130 @@
+using Data.SeaHavenIndustries.Enums;
+using FluentAssertions;
+using SeaHaven.DataServices.Dto;
+using SeaHaven.DataServices.Interfaces;
+using SeaHaven.Services.Constants;
+using SeaHaven.Services.Implementation;
+using SeaHaven.Services.DTOs;
+using SeaHaven.Services.Interfaces;
+using System.Security.Claims;
+using Xunit;
+
+namespace SeaHaven.Services.Tests;
+
+public sealed class TeamPermissionServiceTests
+{
+    [Fact]
+    public async Task GetProfile_ReturnsEveryKeyAndRoleDefaults()
+    {
+        var data = new FakeDataService("u1", "Dispatcher");
+        var result = await Service(data).GetProfileAsync("u1", Admin(), CancellationToken.None);
+
+        result.IsSuccess.Should().BeTrue();
+        result.Value!.Permissions.Should().HaveCount(22);
+        result.Value.Permissions.Single(p => p.PermissionKey == TeamPermissionKeys.CreateSites).IsGranted.Should().BeTrue();
+        result.Value.Permissions.Single(p => p.PermissionKey == TeamPermissionKeys.DeleteSites).IsGranted.Should().BeFalse();
+        result.Value.Permissions.Should().OnlyContain(p => p.OverrideState == UserPermissionState.Unset);
+    }
+
+    [Fact]
+    public async Task SetOverride_ChangesOnlyOnePermissionAndPersistsCanonicalKey()
+    {
+        var data = new FakeDataService("u1", "Dispatcher");
+        var result = await Service(data).SetOverrideAsync(
+            "u1", "DELETEsites", UserPermissionState.Allow, Admin(), CancellationToken.None);
+
+        result.IsSuccess.Should().BeTrue();
+        result.Value!.Permissions.Single(p => p.PermissionKey == TeamPermissionKeys.DeleteSites).IsGranted.Should().BeTrue();
+        result.Value.Permissions.Single(p => p.PermissionKey == TeamPermissionKeys.DeleteSites).OverrideState.Should().Be(UserPermissionState.Allow);
+        result.Value.Permissions.Single(p => p.PermissionKey == TeamPermissionKeys.CreateSites).IsGranted.Should().BeTrue();
+        data.LastSet.Should().Be(("u1", TeamPermissionKeys.DeleteSites, UserPermissionState.Allow));
+    }
+
+    [Fact]
+    public async Task SetOverride_RejectsUnknownKeyBeforeDataAccess()
+    {
+        var data = new FakeDataService("u1", "Dispatcher");
+        var result = await Service(data).SetOverrideAsync(
+            "u1", "not-a-permission", UserPermissionState.Allow, Admin(), CancellationToken.None);
+
+        result.Status.Should().Be(TeamPermissionResultStatus.InvalidPermissionKey);
+        data.GetCalls.Should().Be(0);
+    }
+
+    [Fact]
+    public async Task NonAdminCannotReadOrWritePermissions()
+    {
+        var data = new FakeDataService("u1", "Dispatcher");
+        var service = Service(data);
+
+        var read = await service.GetProfileAsync("u1", User("Dispatcher"), CancellationToken.None);
+        var write = await service.SetOverrideAsync("u1", TeamPermissionKeys.CreateSites, UserPermissionState.Deny, User("Dispatcher"), CancellationToken.None);
+
+        read.Status.Should().Be(TeamPermissionResultStatus.Forbidden);
+        write.Status.Should().Be(TeamPermissionResultStatus.Forbidden);
+        data.GetCalls.Should().Be(0);
+    }
+
+    [Fact]
+    public async Task UnknownRoleReceivesNoGrantEvenWhenAnOverrideIsSet()
+    {
+        var data = new FakeDataService("u1", "Legacy");
+        var result = await Service(data).SetOverrideAsync(
+            "u1", TeamPermissionKeys.CreateSites, UserPermissionState.Allow, Admin(), CancellationToken.None);
+
+        result.Value!.Permissions.Should().OnlyContain(p => !p.IsGranted);
+    }
+
+    [Fact]
+    public async Task MissingUserReturnsNotFound()
+    {
+        var data = new FakeDataService(null, null);
+        var result = await Service(data).GetProfileAsync("missing", Admin(), CancellationToken.None);
+
+        result.Status.Should().Be(TeamPermissionResultStatus.NotFound);
+    }
+
+    private static TeamPermissionService Service(FakeDataService data) =>
+        new(data, new TeamPermissionPolicy());
+
+    private static ClaimsPrincipal Admin() => User("Admin");
+
+    private static ClaimsPrincipal User(string role) =>
+        new(new ClaimsIdentity(new[] { new Claim(ClaimTypes.Role, role) }, "test"));
+
+    private sealed class FakeDataService : ITeamPermissionOverrideDataService
+    {
+        private readonly string? _userId;
+        private readonly string? _roleName;
+        private readonly Dictionary<string, UserPermissionState> _overrides = new(StringComparer.OrdinalIgnoreCase);
+
+        public FakeDataService(string? userId, string? roleName)
+        {
+            _userId = userId;
+            _roleName = roleName;
+        }
+
+        public int GetCalls { get; private set; }
+        public (string UserId, string PermissionKey, UserPermissionState State)? LastSet { get; private set; }
+
+        public Task<TeamPermissionUserData?> GetUserAsync(string userId, CancellationToken cancellationToken)
+        {
+            GetCalls++;
+            return Task.FromResult<TeamPermissionUserData?>(_userId != userId
+                ? null
+                : new TeamPermissionUserData
+                {
+                    UserId = userId,
+                    RoleName = _roleName,
+                    Overrides = new Dictionary<string, UserPermissionState>(_overrides, StringComparer.OrdinalIgnoreCase)
+                });
+        }
+
+        public Task SetOverrideAsync(string userId, string permissionKey, UserPermissionState state, CancellationToken cancellationToken)
+        {
+            _overrides[permissionKey] = state;
+            LastSet = (userId, permissionKey, state);
+            return Task.CompletedTask;
+        }
+    }
+}
diff --git a/SeaHaven.Services/DTOs/TeamPermissionDTOs.cs b/SeaHaven.Services/DTOs/TeamPermissionDTOs.cs
new file mode 100644
index 0000000..d930a83
--- /dev/null
+++ b/SeaHaven.Services/DTOs/TeamPermissionDTOs.cs
@@ -0,0 +1,49 @@
+using Data.SeaHavenIndustries.Enums;
+
+namespace SeaHaven.Services.DTOs;
+
+public sealed class TeamPermissionProfileDTO
+{
+    public required string UserId { get; init; }
+    public string? RoleName { get; init; }
+    public required IReadOnlyList<TeamPermissionValueDTO> Permissions { get; init; }
+}
+
+public sealed class TeamPermissionValueDTO
+{
+    public required string PermissionKey { get; init; }
+    public UserPermissionState OverrideState { get; init; }
+    public bool IsGranted { get; init; }
+}
+
+public sealed class SetTeamPermissionOverrideDTO
+{
+    public UserPermissionState State { get; init; }
+}
+
+public enum TeamPermissionResultStatus
+{
+    Success,
+    Forbidden,
+    NotFound,
+    InvalidPermissionKey
+}
+
+public sealed class TeamPermissionResult<T>
+{
+    private TeamPermissionResult(TeamPermissionResultStatus status, T? value)
+    {
+        Status = status;
+        Value = value;
+    }
+
+    public TeamPermissionResultStatus Status { get; }
+    public T? Value { get; }
+    public bool IsSuccess => Status == TeamPermissionResultStatus.Success;
+
+    public static TeamPermissionResult<T> Success(T value) =>
+        new(TeamPermissionResultStatus.Success, value);
+
+    public static TeamPermissionResult<T> Failure(TeamPermissionResultStatus status) =>
+        new(status, default);
+}
diff --git a/SeaHaven.Services/Implementation/TeamPermissionService.cs b/SeaHaven.Services/Implementation/TeamPermissionService.cs
new file mode 100644
index 0000000..34e6f26
--- /dev/null
+++ b/SeaHaven.Services/Implementation/TeamPermissionService.cs
@@ -0,0 +1,96 @@
+using Data.SeaHavenIndustries.Enums;
+using SeaHaven.DataServices.Dto;
+using SeaHaven.DataServices.Interfaces;
+using SeaHaven.Services.Constants;
+using SeaHaven.Services.DTOs;
+using SeaHaven.Services.Interfaces;
+using System.Security.Claims;
+
+namespace SeaHaven.Services.Implementation;
+
+public sealed class TeamPermissionService : ITeamPermissionService
+{
+    private readonly ITeamPermissionOverrideDataService _dataService;
+    private readonly ITeamPermissionPolicy _policy;
+
+    public TeamPermissionService(
+        ITeamPermissionOverrideDataService dataService,
+        ITeamPermissionPolicy policy)
+    {
+        _dataService = dataService;
+        _policy = policy;
+    }
+
+    public async Task<TeamPermissionResult<TeamPermissionProfileDTO>> GetProfileAsync(
+        string userId,
+        ClaimsPrincipal caller,
+        CancellationToken cancellationToken)
+    {
+        if (!IsAdmin(caller))
+            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.Forbidden);
+
+        var user = await _dataService.GetUserAsync(userId, cancellationToken);
+        return user is null
+            ? TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.NotFound)
+            : TeamPermissionResult<TeamPermissionProfileDTO>.Success(BuildProfile(user));
+    }
+
+    public async Task<TeamPermissionResult<TeamPermissionProfileDTO>> SetOverrideAsync(
+        string userId,
+        string permissionKey,
+        UserPermissionState state,
+        ClaimsPrincipal caller,
+        CancellationToken cancellationToken)
+    {
+        if (!IsAdmin(caller))
+            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.Forbidden);
+
+        var canonicalKey = TeamPermissionKeys.All.FirstOrDefault(
+            key => string.Equals(key, permissionKey, StringComparison.OrdinalIgnoreCase));
+        if (canonicalKey is null)
+            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(
+                TeamPermissionResultStatus.InvalidPermissionKey);
+
+        var user = await _dataService.GetUserAsync(userId, cancellationToken);
+        if (user is null)
+            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.NotFound);
+
+        await _dataService.SetOverrideAsync(userId, canonicalKey, state, cancellationToken);
+
+        var updatedOverrides = user.Overrides.ToDictionary(
+            pair => pair.Key,
+            pair => pair.Value,
+            StringComparer.OrdinalIgnoreCase);
+        updatedOverrides[canonicalKey] = state;
+
+        return TeamPermissionResult<TeamPermissionProfileDTO>.Success(
+            BuildProfile(new TeamPermissionUserData
+            {
+                UserId = user.UserId,
+                RoleName = user.RoleName,
+                Overrides = updatedOverrides
+            }));
+    }
+
+    private TeamPermissionProfileDTO BuildProfile(TeamPermissionUserData user)
+    {
+        return new TeamPermissionProfileDTO
+        {
+            UserId = user.UserId,
+            RoleName = user.RoleName,
+            Permissions = TeamPermissionKeys.All
+                .Select(key => new TeamPermissionValueDTO
+                {
+                    PermissionKey = key,
+                    OverrideState = user.Overrides.TryGetValue(key, out var state)
+                        ? state
+                        : UserPermissionState.Unset,
+                    IsGranted = _policy.IsAllowed(user.RoleName, key, user.Overrides)
+                })
+                .ToList()
+        };
+    }
+
+    private static bool IsAdmin(ClaimsPrincipal? caller) =>
+        caller?.IsInRole("Admin") == true;
+}
diff --git a/SeaHaven.Services/Interfaces/ITeamPermissionService.cs b/SeaHaven.Services/Interfaces/ITeamPermissionService.cs
new file mode 100644
index 0000000..d4b3892
--- /dev/null
+++ b/SeaHaven.Services/Interfaces/ITeamPermissionService.cs
@@ -0,0 +1,20 @@
+using Data.SeaHavenIndustries.Enums;
+using SeaHaven.Services.DTOs;
+using System.Security.Claims;
+
+namespace SeaHaven.Services.Interfaces;
+
+public interface ITeamPermissionService
+{
+    Task<TeamPermissionResult<TeamPermissionProfileDTO>> GetProfileAsync(
+        string userId,
+        ClaimsPrincipal caller,
+        CancellationToken cancellationToken);
+
+    Task<TeamPermissionResult<TeamPermissionProfileDTO>> SetOverrideAsync(
+        string userId,
+        string permissionKey,
+        UserPermissionState state,
+        ClaimsPrincipal caller,
+        CancellationToken cancellationToken);
+}