diff --git a/SPMS.API/Controllers/AuthController.cs b/SPMS.API/Controllers/AuthController.cs
index 7eac9f4..fdc41e0 100644
--- a/SPMS.API/Controllers/AuthController.cs
+++ b/SPMS.API/Controllers/AuthController.cs
@@ -132,9 +132,10 @@ public class AuthController : ControllerBase
     [Authorize]
     [SwaggerOperation(
         Summary = "비밀번호 변경",
-        Description = "현재 로그인된 관리자의 비밀번호를 변경합니다.")]
-    [SwaggerResponse(200, "비밀번호 변경 성공")]
-    [SwaggerResponse(400, "현재 비밀번호 불일치")]
+        Description = "현재 로그인된 관리자의 비밀번호를 변경합니다. 변경 성공 시 모든 세션이 무효화되며 재로그인이 필요합니다. " +
+                      "비밀번호 정책: 8자 이상, 영문 대/소문자·숫자·특수문자 각 1자 이상, 현재 비밀번호와 동일 불가.")]
+    [SwaggerResponse(200, "비밀번호 변경 성공", typeof(ApiResponse<ChangePasswordResponseDto>))]
+    [SwaggerResponse(400, "현재 비밀번호 불일치 / 정책 위반 / 동일 비밀번호 재사용")]
     [SwaggerResponse(401, "인증되지 않은 요청")]
     public async Task<IActionResult> ChangePasswordAsync([FromBody] ChangePasswordRequestDto request)
     {
@@ -142,7 +143,7 @@ public class AuthController : ControllerBase
         if (string.IsNullOrEmpty(adminIdClaim) || !long.TryParse(adminIdClaim, out var adminId))
             throw SpmsException.Unauthorized("인증 정보가 유효하지 않습니다.");
 
-        await _authService.ChangePasswordAsync(adminId, request);
-        return Ok(ApiResponse.Success());
+        var result = await _authService.ChangePasswordAsync(adminId, request);
+        return Ok(ApiResponse<ChangePasswordResponseDto>.Success(result));
     }
 }
diff --git a/SPMS.Application/DTOs/Auth/ChangePasswordRequestDto.cs b/SPMS.Application/DTOs/Auth/ChangePasswordRequestDto.cs
index 0707e04..7691b7f 100644
--- a/SPMS.Application/DTOs/Auth/ChangePasswordRequestDto.cs
+++ b/SPMS.Application/DTOs/Auth/ChangePasswordRequestDto.cs
@@ -9,5 +9,9 @@ public class ChangePasswordRequestDto
 
     [Required(ErrorMessage = "새 비밀번호를 입력해주세요.")]
     [MinLength(8, ErrorMessage = "비밀번호는 8자 이상이어야 합니다.")]
+    [MaxLength(64, ErrorMessage = "비밀번호는 64자 이하여야 합니다.")]
+    [RegularExpression(
+        @"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[!@#$%^&*()_+\-=\[\]{};':""\\|,.<>\/?]).{8,}$",
+        ErrorMessage = "비밀번호는 영문 대/소문자, 숫자, 특수문자를 각각 1자 이상 포함해야 합니다.")]
     public string NewPassword { get; set; } = string.Empty;
 }
diff --git a/SPMS.Application/DTOs/Auth/ChangePasswordResponseDto.cs b/SPMS.Application/DTOs/Auth/ChangePasswordResponseDto.cs
new file mode 100644
index 0000000..58efa4f
--- /dev/null
+++ b/SPMS.Application/DTOs/Auth/ChangePasswordResponseDto.cs
@@ -0,0 +1,9 @@
+using System.Text.Json.Serialization;
+
+namespace SPMS.Application.DTOs.Auth;
+
+public class ChangePasswordResponseDto
+{
+    [JsonPropertyName("re_login_required")]
+    public bool ReLoginRequired { get; set; }
+}
diff --git a/SPMS.Application/Interfaces/IAuthService.cs b/SPMS.Application/Interfaces/IAuthService.cs
index cf663c5..a41299a 100644
--- a/SPMS.Application/Interfaces/IAuthService.cs
+++ b/SPMS.Application/Interfaces/IAuthService.cs
@@ -9,7 +9,7 @@ public interface IAuthService
     Task<LoginResponseDto> LoginAsync(LoginRequestDto request);
     Task<TokenRefreshResponseDto> RefreshTokenAsync(TokenRefreshRequestDto request);
     Task LogoutAsync(long adminId, string accessToken);
-    Task ChangePasswordAsync(long adminId, ChangePasswordRequestDto request);
+    Task<ChangePasswordResponseDto> ChangePasswordAsync(long adminId, ChangePasswordRequestDto request);
     Task<EmailCheckResponseDto> CheckEmailAsync(EmailCheckRequestDto request);
     Task<EmailVerifyResponseDto> VerifyEmailAsync(EmailVerifyRequestDto request);
     Task<EmailResendResponseDto> ResendVerificationAsync(EmailResendRequestDto request);
diff --git a/SPMS.Application/Services/AuthService.cs b/SPMS.Application/Services/AuthService.cs
index d05b3a3..cb82514 100644
--- a/SPMS.Application/Services/AuthService.cs
+++ b/SPMS.Application/Services/AuthService.cs
@@ -315,7 +315,7 @@ public class AuthService : IAuthService
         }
     }
 
-    public async Task ChangePasswordAsync(long adminId, ChangePasswordRequestDto request)
+    public async Task<ChangePasswordResponseDto> ChangePasswordAsync(long adminId, ChangePasswordRequestDto request)
     {
         // 1. 관리자 조회
         var admin = await _adminRepository.GetByIdAsync(adminId);
@@ -336,19 +336,37 @@ public class AuthService : IAuthService
                 400);
         }
 
-        // 3. 새 비밀번호 해싱 및 저장
+        // 3. 동일 비밀번호 재사용 금지
+        if (BCrypt.Net.BCrypt.Verify(request.NewPassword, admin.Password))
+        {
+            throw new SpmsException(
+                ErrorCodes.PasswordReuseForbidden,
+                "현재 비밀번호와 동일한 비밀번호는 사용할 수 없습니다.",
+                400);
+        }
+
+        // 4. 새 비밀번호 해싱 및 저장
         admin.Password = BCrypt.Net.BCrypt.HashPassword(request.NewPassword);
 
-        // 4. 강제변경 플래그 해제
+        // 5. 강제변경 플래그 해제
         if (admin.MustChangePassword)
         {
             admin.MustChangePassword = false;
             admin.TempPasswordIssuedAt = null;
         }
 
+        // 6. 세션 무효화 — Refresh Token 삭제
+        admin.RefreshToken = null;
+        admin.RefreshTokenExpiresAt = null;
+
         _adminRepository.Update(admin);
         await _unitOfWork.SaveChangesAsync();
-        _logger.LogInformation("[AUTH] 비밀번호 변경 — AdminId: {AdminId}", adminId);
+        _logger.LogInformation("[AUTH] 비밀번호 변경 + 세션 무효화 — AdminId: {AdminId}", adminId);
+
+        return new ChangePasswordResponseDto
+        {
+            ReLoginRequired = true
+        };
     }
 
     public async Task<EmailCheckResponseDto> CheckEmailAsync(EmailCheckRequestDto request)
diff --git a/SPMS.Domain/Common/ErrorCodes.cs b/SPMS.Domain/Common/ErrorCodes.cs
index 0fb55d5..9f0f670 100644
--- a/SPMS.Domain/Common/ErrorCodes.cs
+++ b/SPMS.Domain/Common/ErrorCodes.cs
@@ -31,6 +31,8 @@ public static class ErrorCodes
     // === Account (2) ===
     public const string PasswordValidationFailed = "121";
     public const string ResetTokenError = "122";
+    public const string PasswordPolicyViolation = "123";
+    public const string PasswordReuseForbidden = "124";
 
     // === Service (3) ===
     public const string DecryptionFailed = "131";