diff --git a/backend/src/main/java/net/pengcook/user/controller/UserController.java b/backend/src/main/java/net/pengcook/user/controller/UserController.java
index fb1317dd..cd8a2312 100644
--- a/backend/src/main/java/net/pengcook/user/controller/UserController.java
+++ b/backend/src/main/java/net/pengcook/user/controller/UserController.java
@@ -1,11 +1,14 @@
 package net.pengcook.user.controller;
 
+import jakarta.validation.constraints.NotBlank;
 import lombok.RequiredArgsConstructor;
 import net.pengcook.authentication.domain.UserInfo;
 import net.pengcook.authentication.resolver.LoginUser;
 import net.pengcook.user.dto.UserResponse;
+import net.pengcook.user.dto.UsernameCheckResponse;
 import net.pengcook.user.service.UserService;
 import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
 import org.springframework.web.bind.annotation.RestController;
 
 @RestController
@@ -18,4 +21,9 @@ public class UserController {
     public UserResponse getUserProfile(@LoginUser UserInfo userInfo) {
         return userService.getUserById(userInfo.getId());
     }
+
+    @GetMapping("/api/user/username/check")
+    public UsernameCheckResponse checkUsername(@RequestParam @NotBlank String username) {
+        return userService.checkUsername(username);
+    }
 }
diff --git a/backend/src/main/java/net/pengcook/user/dto/UsernameCheckResponse.java b/backend/src/main/java/net/pengcook/user/dto/UsernameCheckResponse.java
new file mode 100644
index 00000000..a18494fa
--- /dev/null
+++ b/backend/src/main/java/net/pengcook/user/dto/UsernameCheckResponse.java
@@ -0,0 +1,4 @@
+package net.pengcook.user.dto;
+
+public record UsernameCheckResponse(boolean available) {
+}
diff --git a/backend/src/main/java/net/pengcook/user/repository/UserRepository.java b/backend/src/main/java/net/pengcook/user/repository/UserRepository.java
index b8eda9fa..4b15a988 100644
--- a/backend/src/main/java/net/pengcook/user/repository/UserRepository.java
+++ b/backend/src/main/java/net/pengcook/user/repository/UserRepository.java
@@ -11,4 +11,6 @@ public interface UserRepository extends JpaRepository<User, Long> {
     Optional<User> findByEmail(String email);
 
     boolean existsByEmail(String email);
+
+    boolean existsByUsername(String username);
 }
diff --git a/backend/src/main/java/net/pengcook/user/service/UserService.java b/backend/src/main/java/net/pengcook/user/service/UserService.java
index 8f1ca693..5c4bc48b 100644
--- a/backend/src/main/java/net/pengcook/user/service/UserService.java
+++ b/backend/src/main/java/net/pengcook/user/service/UserService.java
@@ -3,6 +3,7 @@
 import lombok.AllArgsConstructor;
 import net.pengcook.user.domain.User;
 import net.pengcook.user.dto.UserResponse;
+import net.pengcook.user.dto.UsernameCheckResponse;
 import net.pengcook.user.repository.UserRepository;
 import org.springframework.stereotype.Service;
 
@@ -16,4 +17,9 @@ public UserResponse getUserById(long id) {
         User user = userRepository.findById(id).orElseThrow();
         return new UserResponse(user);
     }
+
+    public UsernameCheckResponse checkUsername(String username) {
+        boolean userExists = userRepository.existsByUsername(username);
+        return new UsernameCheckResponse(!userExists);
+    }
 }
diff --git a/backend/src/test/java/net/pengcook/user/controller/UserControllerTest.java b/backend/src/test/java/net/pengcook/user/controller/UserControllerTest.java
index a06f6165..4941e14d 100644
--- a/backend/src/test/java/net/pengcook/user/controller/UserControllerTest.java
+++ b/backend/src/test/java/net/pengcook/user/controller/UserControllerTest.java
@@ -12,6 +12,7 @@
 import net.pengcook.authentication.annotation.WithLoginUser;
 import net.pengcook.authentication.annotation.WithLoginUserTest;
 import net.pengcook.user.dto.UserResponse;
+import org.hamcrest.Matchers;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
@@ -60,4 +61,42 @@ void getUserProfile() {
 
         assertThat(actual).isEqualTo(expected);
     }
+
+    @Test
+    @DisplayName("username이 중복되지 않으면 사용 가능하다.")
+    void checkUsername() {
+        RestAssured.given(spec).log().all()
+                .filter(document(DEFAULT_RESTDOCS_PATH,
+                        "username이 중복되면 사용 불가능하다.",
+                        "사용자 이름 중복 체크 API",
+                        responseFields(
+                                fieldWithPath("available").description("사용 가능 여부")
+                        )
+                ))
+                .contentType(ContentType.JSON)
+                .queryParam("username", "new_face")
+                .when().get("/api/user/username/check")
+                .then().log().all()
+                .statusCode(200)
+                .body("available", Matchers.is(true));
+    }
+
+    @Test
+    @DisplayName("username이 중복되면 사용 불가능하다.")
+    void checkUsernameWhenDuplicateUsername() {
+        RestAssured.given(spec).log().all()
+                .filter(document(DEFAULT_RESTDOCS_PATH,
+                        "username이 중복되면 사용 불가능하다.",
+                        "사용자 이름 중복 체크 API",
+                        responseFields(
+                                fieldWithPath("available").description("사용 가능 여부")
+                        )
+                ))
+                .contentType(ContentType.JSON)
+                .queryParam("username", "loki")
+                .when().get("/api/user/username/check")
+                .then().log().all()
+                .statusCode(200)
+                .body("available", Matchers.is(false));
+    }
 }
diff --git a/backend/src/test/java/net/pengcook/user/service/UserServiceTest.java b/backend/src/test/java/net/pengcook/user/service/UserServiceTest.java
index 56dc40fa..26d05957 100644
--- a/backend/src/test/java/net/pengcook/user/service/UserServiceTest.java
+++ b/backend/src/test/java/net/pengcook/user/service/UserServiceTest.java
@@ -6,6 +6,7 @@
 import java.time.LocalDate;
 import java.util.NoSuchElementException;
 import net.pengcook.user.dto.UserResponse;
+import net.pengcook.user.dto.UsernameCheckResponse;
 import net.pengcook.user.repository.UserRepository;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
@@ -53,4 +54,24 @@ void getUserByIdWhenNotExistId() {
         assertThatThrownBy(() -> userService.getUserById(id))
                 .isInstanceOf(NoSuchElementException.class);
     }
+    
+    @Test
+    @DisplayName("중복되지 않은 username을 입력하면 사용 가능하다")
+    void checkUsername() {
+        String username = "new_face";
+
+        UsernameCheckResponse usernameCheckResponse = userService.checkUsername(username);
+
+        assertThat(usernameCheckResponse.available()).isTrue();
+    }
+
+    @Test
+    @DisplayName("중복된 username을 입력하면 사용 불가능하다")
+    void checkUsernameWhenDuplicatedUsername() {
+        String username = "loki";
+
+        UsernameCheckResponse usernameCheckResponse = userService.checkUsername(username);
+
+        assertThat(usernameCheckResponse.available()).isFalse();
+    }
 }