diff --git a/src/main/java/com/cmc/mercury/domain/user/entity/Adjective.java b/src/main/java/com/cmc/mercury/domain/user/entity/Adjective.java
new file mode 100644
index 0000000..bbb320b
--- /dev/null
+++ b/src/main/java/com/cmc/mercury/domain/user/entity/Adjective.java
@@ -0,0 +1,20 @@
+package com.cmc.mercury.domain.user.entity;
+
+import jakarta.persistence.*;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Entity
+@Getter
+@RequiredArgsConstructor(access = AccessLevel.PROTECTED)
+public class Adjective {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "adj_id")
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String word;
+}
diff --git a/src/main/java/com/cmc/mercury/domain/user/entity/Noun.java b/src/main/java/com/cmc/mercury/domain/user/entity/Noun.java
new file mode 100644
index 0000000..333e1cb
--- /dev/null
+++ b/src/main/java/com/cmc/mercury/domain/user/entity/Noun.java
@@ -0,0 +1,20 @@
+package com.cmc.mercury.domain.user.entity;
+
+import jakarta.persistence.*;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Entity
+@Getter
+@RequiredArgsConstructor(access = AccessLevel.PROTECTED)
+public class Noun {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "noun_id")
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String word;
+}
diff --git a/src/main/java/com/cmc/mercury/domain/user/entity/User.java b/src/main/java/com/cmc/mercury/domain/user/entity/User.java
index 0a63524..f3c58b0 100644
--- a/src/main/java/com/cmc/mercury/domain/user/entity/User.java
+++ b/src/main/java/com/cmc/mercury/domain/user/entity/User.java
@@ -20,7 +20,7 @@ public class User extends BaseEntity {
     @Column(name = "user_id")
     private Long id;
 
-//    @Column(nullable = false)
+    @Column(nullable = false)
 //    @Column(length = 30) // DB 컬럼 길이 제한 -> 바이트 단위라 한글을 위해 여유 있게
     private String nickname;
 
@@ -49,10 +49,10 @@ public class User extends BaseEntity {
     private UserStatus userStatus;
 
     @Builder
-    public User(String email, OAuthType oauthType,
+    public User(String email, String nickname, OAuthType oauthType,
                 String oauthId, UserStatus userStatus) {
         this.email = email;
-        this.nickname = "Mercury";
+        this.nickname = nickname;
         this.oauthType = oauthType;
         this.oauthId = oauthId;
         this.userStatus = userStatus;
@@ -61,9 +61,9 @@ public User(String email, OAuthType oauthType,
 
     // 게스트용 생성자
     @Builder(builderMethodName = "TestUserBuilder", buildMethodName = "TestUserBuild")
-    public User(String email) {
+    public User(String email, String nickname) {
         this.email = email;
-        this.nickname = "TestUser";
+        this.nickname = nickname;
         this.oauthType = OAuthType.TEST;
         this.oauthId = UUID.randomUUID().toString();;
         this.userStatus = UserStatus.ACTIVE;
diff --git a/src/main/java/com/cmc/mercury/domain/user/repository/AdjectiveRepository.java b/src/main/java/com/cmc/mercury/domain/user/repository/AdjectiveRepository.java
new file mode 100644
index 0000000..6465554
--- /dev/null
+++ b/src/main/java/com/cmc/mercury/domain/user/repository/AdjectiveRepository.java
@@ -0,0 +1,13 @@
+package com.cmc.mercury.domain.user.repository;
+
+import com.cmc.mercury.domain.user.entity.Adjective;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface AdjectiveRepository extends JpaRepository<Adjective, Long> {
+
+    @Query("SELECT a FROM Adjective a ORDER BY FUNCTION('RAND') LIMIT 1")
+    Adjective findRandomAdjective();
+}
diff --git a/src/main/java/com/cmc/mercury/domain/user/repository/NounRepository.java b/src/main/java/com/cmc/mercury/domain/user/repository/NounRepository.java
new file mode 100644
index 0000000..ee56944
--- /dev/null
+++ b/src/main/java/com/cmc/mercury/domain/user/repository/NounRepository.java
@@ -0,0 +1,13 @@
+package com.cmc.mercury.domain.user.repository;
+
+import com.cmc.mercury.domain.user.entity.Noun;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface NounRepository extends JpaRepository<Noun, Long> {
+
+    @Query("SELECT n FROM Noun n ORDER BY FUNCTION('RAND') LIMIT 1")
+    Noun findRandomNoun();
+}
diff --git a/src/main/java/com/cmc/mercury/domain/user/repository/UserRepository.java b/src/main/java/com/cmc/mercury/domain/user/repository/UserRepository.java
index 34bb36e..2a3ffbf 100644
--- a/src/main/java/com/cmc/mercury/domain/user/repository/UserRepository.java
+++ b/src/main/java/com/cmc/mercury/domain/user/repository/UserRepository.java
@@ -19,4 +19,6 @@ public interface UserRepository extends JpaRepository<User, Long> {
     boolean existsByEmailAndOauthType(String email, OAuthType oauthType);
 
     Optional<User> findByEmailAndOauthType(String email, OAuthType oAuthType);
+
+    boolean existsByNickname(String nickname);
 }
diff --git a/src/main/java/com/cmc/mercury/domain/user/service/UserService.java b/src/main/java/com/cmc/mercury/domain/user/service/UserService.java
index d1c265e..d3a7b0d 100644
--- a/src/main/java/com/cmc/mercury/domain/user/service/UserService.java
+++ b/src/main/java/com/cmc/mercury/domain/user/service/UserService.java
@@ -2,9 +2,9 @@
 
 import com.cmc.mercury.domain.mypage.entity.Habit;
 import com.cmc.mercury.domain.mypage.repository.HabitRepository;
-import com.cmc.mercury.domain.user.entity.OAuthType;
-import com.cmc.mercury.domain.user.entity.User;
-import com.cmc.mercury.domain.user.entity.UserStatus;
+import com.cmc.mercury.domain.user.entity.*;
+import com.cmc.mercury.domain.user.repository.AdjectiveRepository;
+import com.cmc.mercury.domain.user.repository.NounRepository;
 import com.cmc.mercury.domain.user.repository.UserRepository;
 import com.cmc.mercury.domain.user.response.UserTestRequest;
 import com.cmc.mercury.global.exception.CustomException;
@@ -37,6 +37,8 @@ public class UserService {
     private final JwtProvider jwtProvider;
     private final HttpServletResponse response;
     private final HabitRepository habitRepository;
+    private final AdjectiveRepository adjectiveRepository;
+    private final NounRepository nounRepository;
 
     @Transactional
     public User createTestUser(UserTestRequest request) {
@@ -62,6 +64,7 @@ public User createTestUser(UserTestRequest request) {
 
         User newUser = User.TestUserBuilder()
                         .email(request.email())
+                        .nickname(assignNickname())
                         .TestUserBuild();
 
         User savedUser = userRepository.save(newUser);
@@ -131,4 +134,18 @@ public User getUser(String accessToken) {
         // 유효성 검증이 완료된 토큰에서 user 추출
         return jwtProvider.getUserFromToken(accessToken);
     }
+
+    private String assignNickname() {
+
+        String nickname;
+        do {
+            Adjective adj = adjectiveRepository.findRandomAdjective();
+            Noun noun = nounRepository.findRandomNoun();
+            nickname = adj.getWord() + noun.getWord();
+
+            // 닉네임 중복인지 체크
+        } while (userRepository.existsByNickname(nickname));
+
+        return nickname;
+    }
 }
diff --git a/src/main/java/com/cmc/mercury/global/oauth/service/CustomOAuth2UserService.java b/src/main/java/com/cmc/mercury/global/oauth/service/CustomOAuth2UserService.java
index 13c8ba4..2bf5e5e 100644
--- a/src/main/java/com/cmc/mercury/global/oauth/service/CustomOAuth2UserService.java
+++ b/src/main/java/com/cmc/mercury/global/oauth/service/CustomOAuth2UserService.java
@@ -3,9 +3,9 @@
 import com.auth0.jwt.interfaces.DecodedJWT;
 import com.cmc.mercury.domain.mypage.entity.Habit;
 import com.cmc.mercury.domain.mypage.repository.HabitRepository;
-import com.cmc.mercury.domain.user.entity.OAuthType;
-import com.cmc.mercury.domain.user.entity.User;
-import com.cmc.mercury.domain.user.entity.UserStatus;
+import com.cmc.mercury.domain.user.entity.*;
+import com.cmc.mercury.domain.user.repository.AdjectiveRepository;
+import com.cmc.mercury.domain.user.repository.NounRepository;
 import com.cmc.mercury.domain.user.repository.UserRepository;
 import com.cmc.mercury.global.exception.CustomException;
 import com.cmc.mercury.global.exception.ErrorCode;
@@ -37,6 +37,8 @@ public class CustomOAuth2UserService extends DefaultOAuth2UserService {
     private final UserRepository userRepository;
     private final AppleIdTokenVerifier appleIdTokenVerifier;
     private final HabitRepository habitRepository;
+    private final AdjectiveRepository adjectiveRepository;
+    private final NounRepository nounRepository;
 
     @Override
     public OAuth2User loadUser(OAuth2UserRequest userRequest) throws OAuth2AuthenticationException {
@@ -155,6 +157,7 @@ private User createUser(OAuth2UserInfo oAuth2UserInfo) {
 
         User user = User.builder()
                 .email(oAuth2UserInfo.getEmail())
+                .nickname(assignNickname())
                 .oauthType(oAuth2UserInfo.getOAuthType())
                 .oauthId(oAuth2UserInfo.getOAuthId())
                 .userStatus(UserStatus.ACTIVE)
@@ -171,4 +174,18 @@ private User createUser(OAuth2UserInfo oAuth2UserInfo) {
 
         return savedUser;
     }
+
+    private String assignNickname() {
+
+        String nickname;
+        do {
+            Adjective adj = adjectiveRepository.findRandomAdjective();
+            Noun noun = nounRepository.findRandomNoun();
+            nickname = adj.getWord() + noun.getWord();
+
+            // 닉네임 중복인지 체크
+        } while (userRepository.existsByNickname(nickname));
+
+        return nickname;
+    }
 }