diff --git a/tests/SIGCM2.Api.Tests/Usuarios/DeactivateReactivateEndpointTests.cs b/tests/SIGCM2.Api.Tests/Usuarios/DeactivateReactivateEndpointTests.cs
new file mode 100644
index 0000000..47a6e6d
--- /dev/null
+++ b/tests/SIGCM2.Api.Tests/Usuarios/DeactivateReactivateEndpointTests.cs
@@ -0,0 +1,216 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Text.Json;
+using Dapper;
+using Microsoft.Data.SqlClient;
+using SIGCM2.TestSupport;
+
+namespace SIGCM2.Api.Tests.Usuarios;
+
+/// <summary>
+/// Integration tests for PATCH /api/v1/users/{id}/deactivate and /reactivate (UDT-008 B5).
+/// </summary>
+[Collection("ApiIntegration")]
+public sealed class DeactivateReactivateEndpointTests : IAsyncLifetime
+{
+    private const string TestConnectionString =
+        "Server=TECNICA3;Database=SIGCM2_Test;User Id=desarrollo;Password=desarrollo2026;TrustServerCertificate=True;";
+
+    private readonly HttpClient _client;
+    private readonly SqlTestFixture _db;
+
+    public DeactivateReactivateEndpointTests(TestWebAppFactory factory)
+    {
+        _client = factory.CreateClient();
+        _db = new SqlTestFixture(TestConnectionString);
+    }
+
+    public async Task InitializeAsync() => await _db.InitializeAsync();
+    public async Task DisposeAsync() => await _db.DisposeAsync();
+
+    private async Task<string> GetAdminTokenAsync()
+    {
+        var response = await _client.PostAsJsonAsync("/api/v1/auth/login",
+            new { username = "admin", password = "@Diego550@" });
+        response.EnsureSuccessStatusCode();
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        return json.GetProperty("accessToken").GetString()!;
+    }
+
+    private async Task<int> GetAdminIdAsync()
+    {
+        await using var conn = new SqlConnection(TestConnectionString);
+        await conn.OpenAsync();
+        return await conn.ExecuteScalarAsync<int>("SELECT Id FROM dbo.Usuario WHERE Username = 'admin'");
+    }
+
+    private async Task<int> SeedCajeroAsync(string username, bool activo = true)
+    {
+        await using var conn = new SqlConnection(TestConnectionString);
+        await conn.OpenAsync();
+        var activoVal = activo ? 1 : 0;
+        return await conn.ExecuteScalarAsync<int>($"""
+            IF NOT EXISTS (SELECT 1 FROM dbo.Usuario WHERE Username = '{username}')
+            INSERT INTO dbo.Usuario (Username, PasswordHash, Nombre, Apellido, Rol, PermisosJson, Activo, MustChangePassword)
+            VALUES ('{username}', '$2a$12$rmq6tlSAQ8WXhR2CwLCSeuwCJKz/.8Eab95UQCUNfwe4dokeOqMcW', 'Test', 'Usuario', 'cajero', '[]', {activoVal}, 0);
+            SELECT Id FROM dbo.Usuario WHERE Username = '{username}'
+            """);
+    }
+
+    private async Task<string> GetCajeroTokenAsync()
+    {
+        await SeedCajeroAsync("cajero_deact_auth");
+        var response = await _client.PostAsJsonAsync("/api/v1/auth/login",
+            new { username = "cajero_deact_auth", password = "@Diego550@" });
+        response.EnsureSuccessStatusCode();
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        return json.GetProperty("accessToken").GetString()!;
+    }
+
+    // ── deactivate ────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task PATCH_Deactivate_200_Returns_UserDetail_Activo_False()
+    {
+        var token = await GetAdminTokenAsync();
+        var targetId = await SeedCajeroAsync("cajero_deact_happy", true);
+
+        var request = new HttpRequestMessage(HttpMethod.Patch, $"/api/v1/users/{targetId}/deactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        Assert.False(json.GetProperty("activo").GetBoolean());
+    }
+
+    [Fact]
+    public async Task PATCH_Deactivate_Idempotent_Returns_200()
+    {
+        var token = await GetAdminTokenAsync();
+        var targetId = await SeedCajeroAsync("cajero_deact_idempotent", false); // already inactive
+
+        var request = new HttpRequestMessage(HttpMethod.Patch, $"/api/v1/users/{targetId}/deactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        Assert.False(json.GetProperty("activo").GetBoolean());
+    }
+
+    [Fact]
+    public async Task PATCH_Deactivate_400_Last_Admin_Lockout()
+    {
+        var token = await GetAdminTokenAsync();
+        var adminId = await GetAdminIdAsync();
+
+        var request = new HttpRequestMessage(HttpMethod.Patch, $"/api/v1/users/{adminId}/deactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+        var body = await response.Content.ReadAsStringAsync();
+        Assert.Contains("last-admin-lockout", body, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task PATCH_Deactivate_404_Not_Found()
+    {
+        var token = await GetAdminTokenAsync();
+        var request = new HttpRequestMessage(HttpMethod.Patch, "/api/v1/users/9999/deactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task PATCH_Deactivate_401_No_Auth()
+    {
+        var response = await _client.SendAsync(new HttpRequestMessage(HttpMethod.Patch, "/api/v1/users/1/deactivate"));
+        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task PATCH_Deactivate_403_No_Permission()
+    {
+        var token = await GetCajeroTokenAsync();
+        var request = new HttpRequestMessage(HttpMethod.Patch, "/api/v1/users/1/deactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+    }
+
+    // ── reactivate ────────────────────────────────────────────────────────────
+
+    [Fact]
+    public async Task PATCH_Reactivate_200_Returns_UserDetail_Activo_True()
+    {
+        var token = await GetAdminTokenAsync();
+        var targetId = await SeedCajeroAsync("cajero_react_happy", false); // inactive
+
+        var request = new HttpRequestMessage(HttpMethod.Patch, $"/api/v1/users/{targetId}/reactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        Assert.True(json.GetProperty("activo").GetBoolean());
+    }
+
+    [Fact]
+    public async Task PATCH_Reactivate_Idempotent_Returns_200()
+    {
+        var token = await GetAdminTokenAsync();
+        var targetId = await SeedCajeroAsync("cajero_react_idempotent", true); // already active
+
+        var request = new HttpRequestMessage(HttpMethod.Patch, $"/api/v1/users/{targetId}/reactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var json = await response.Content.ReadFromJsonAsync<JsonElement>();
+        Assert.True(json.GetProperty("activo").GetBoolean());
+    }
+
+    [Fact]
+    public async Task PATCH_Reactivate_404_Not_Found()
+    {
+        var token = await GetAdminTokenAsync();
+        var request = new HttpRequestMessage(HttpMethod.Patch, "/api/v1/users/9999/reactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task PATCH_Reactivate_401_No_Auth()
+    {
+        var response = await _client.SendAsync(new HttpRequestMessage(HttpMethod.Patch, "/api/v1/users/1/reactivate"));
+        Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task PATCH_Reactivate_403_No_Permission()
+    {
+        var token = await GetCajeroTokenAsync();
+        var request = new HttpRequestMessage(HttpMethod.Patch, "/api/v1/users/1/reactivate");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+        var response = await _client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Usuarios/DeactivateUsuarioCommandHandlerTests.cs b/tests/SIGCM2.Application.Tests/Usuarios/DeactivateUsuarioCommandHandlerTests.cs
new file mode 100644
index 0000000..a9161a3
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Usuarios/DeactivateUsuarioCommandHandlerTests.cs
@@ -0,0 +1,97 @@
+using NSubstitute;
+using SIGCM2.Application.Abstractions.Persistence;
+using SIGCM2.Application.Common;
+using SIGCM2.Application.Usuarios.Deactivate;
+using SIGCM2.Domain.Entities;
+using SIGCM2.Domain.Exceptions;
+
+namespace SIGCM2.Application.Tests.Usuarios;
+
+public class DeactivateUsuarioCommandHandlerTests
+{
+    private readonly IUsuarioRepository _repo = Substitute.For<IUsuarioRepository>();
+    private readonly IRefreshTokenRepository _refreshRepo = Substitute.For<IRefreshTokenRepository>();
+    private readonly DeactivateUsuarioCommandHandler _handler;
+
+    public DeactivateUsuarioCommandHandlerTests()
+    {
+        _handler = new DeactivateUsuarioCommandHandler(_repo, _refreshRepo);
+        _repo.CountActiveAdminsAsync(Arg.Any<CancellationToken>()).Returns(2);
+    }
+
+    private static Usuario MakeUser(int id = 5, string rol = "cajero", bool activo = true)
+        => new(id, "user" + id, "$2a$12$hash", "Test", "User", null, rol, "[]", activo);
+
+    [Fact]
+    public async Task Handle_Deactivates_Active_User_Returns_Activo_False()
+    {
+        var target = MakeUser(5, "cajero", true);
+        var deactivated = MakeUser(5, "cajero", false);
+
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(target);
+        _repo.GetDetailAsync(5, Arg.Any<CancellationToken>()).Returns(deactivated);
+
+        var result = await _handler.Handle(new DeactivateUsuarioCommand(5));
+
+        Assert.False(result.Activo);
+        await _repo.Received(1).UpdateAsync(5, Arg.Any<UpdateUsuarioFields>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_Idempotent_When_Already_Inactive_No_FechaModificacion_Change()
+    {
+        var target = MakeUser(5, "cajero", false); // already inactive
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(target);
+
+        var result = await _handler.Handle(new DeactivateUsuarioCommand(5));
+
+        // Idempotent: should NOT call UpdateAsync
+        await _repo.DidNotReceive().UpdateAsync(Arg.Any<int>(), Arg.Any<UpdateUsuarioFields>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
+        Assert.False(result.Activo);
+    }
+
+    [Fact]
+    public async Task Handle_Throws_LastAdminLockoutException_When_Last_Admin()
+    {
+        var lastAdmin = MakeUser(1, "admin", true);
+        _repo.GetByIdAsync(1, Arg.Any<CancellationToken>()).Returns(lastAdmin);
+        _repo.CountActiveAdminsAsync(Arg.Any<CancellationToken>()).Returns(1);
+
+        await Assert.ThrowsAsync<LastAdminLockoutException>(
+            () => _handler.Handle(new DeactivateUsuarioCommand(1)));
+    }
+
+    [Fact]
+    public async Task Handle_Revokes_Refresh_Tokens_When_Deactivating_Active_User()
+    {
+        var target = MakeUser(5, "cajero", true);
+        var deactivated = MakeUser(5, "cajero", false);
+
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(target);
+        _repo.GetDetailAsync(5, Arg.Any<CancellationToken>()).Returns(deactivated);
+
+        await _handler.Handle(new DeactivateUsuarioCommand(5));
+
+        await _refreshRepo.Received(1).RevokeAllActiveForUserAsync(5, Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_Does_NOT_Revoke_Tokens_When_Already_Inactive_Idempotent()
+    {
+        var target = MakeUser(5, "cajero", false); // already inactive
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(target);
+
+        await _handler.Handle(new DeactivateUsuarioCommand(5));
+
+        await _refreshRepo.DidNotReceive().RevokeAllActiveForUserAsync(Arg.Any<int>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_Throws_UsuarioNotFoundException_When_Not_Found()
+    {
+        _repo.GetByIdAsync(9999, Arg.Any<CancellationToken>()).Returns((Usuario?)null);
+
+        await Assert.ThrowsAsync<UsuarioNotFoundException>(
+            () => _handler.Handle(new DeactivateUsuarioCommand(9999)));
+    }
+}
diff --git a/tests/SIGCM2.Application.Tests/Usuarios/ReactivateUsuarioCommandHandlerTests.cs b/tests/SIGCM2.Application.Tests/Usuarios/ReactivateUsuarioCommandHandlerTests.cs
new file mode 100644
index 0000000..20cc2ca
--- /dev/null
+++ b/tests/SIGCM2.Application.Tests/Usuarios/ReactivateUsuarioCommandHandlerTests.cs
@@ -0,0 +1,58 @@
+using NSubstitute;
+using SIGCM2.Application.Abstractions.Persistence;
+using SIGCM2.Application.Common;
+using SIGCM2.Application.Usuarios.Reactivate;
+using SIGCM2.Domain.Entities;
+using SIGCM2.Domain.Exceptions;
+
+namespace SIGCM2.Application.Tests.Usuarios;
+
+public class ReactivateUsuarioCommandHandlerTests
+{
+    private readonly IUsuarioRepository _repo = Substitute.For<IUsuarioRepository>();
+    private readonly ReactivateUsuarioCommandHandler _handler;
+
+    public ReactivateUsuarioCommandHandlerTests()
+    {
+        _handler = new ReactivateUsuarioCommandHandler(_repo);
+    }
+
+    private static Usuario MakeUser(int id = 5, bool activo = false)
+        => new(id, "user" + id, "$2a$12$hash", "Test", "User", null, "cajero", "[]", activo);
+
+    [Fact]
+    public async Task Handle_Reactivates_Inactive_User_Returns_Activo_True()
+    {
+        var target = MakeUser(5, false);
+        var reactivated = MakeUser(5, true);
+
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(target);
+        _repo.GetDetailAsync(5, Arg.Any<CancellationToken>()).Returns(reactivated);
+
+        var result = await _handler.Handle(new ReactivateUsuarioCommand(5));
+
+        Assert.True(result.Activo);
+        await _repo.Received(1).UpdateAsync(5, Arg.Any<UpdateUsuarioFields>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
+    }
+
+    [Fact]
+    public async Task Handle_Idempotent_When_Already_Active()
+    {
+        var target = MakeUser(5, true); // already active
+        _repo.GetByIdAsync(5, Arg.Any<CancellationToken>()).Returns(target);
+
+        var result = await _handler.Handle(new ReactivateUsuarioCommand(5));
+
+        await _repo.DidNotReceive().UpdateAsync(Arg.Any<int>(), Arg.Any<UpdateUsuarioFields>(), Arg.Any<DateTime>(), Arg.Any<CancellationToken>());
+        Assert.True(result.Activo);
+    }
+
+    [Fact]
+    public async Task Handle_Throws_UsuarioNotFoundException_When_Not_Found()
+    {
+        _repo.GetByIdAsync(9999, Arg.Any<CancellationToken>()).Returns((Usuario?)null);
+
+        await Assert.ThrowsAsync<UsuarioNotFoundException>(
+            () => _handler.Handle(new ReactivateUsuarioCommand(9999)));
+    }
+}