diff --git a/src/api/auth.ts b/src/api/auth.ts
index 4efbb17..920fcf9 100644
--- a/src/api/auth.ts
+++ b/src/api/auth.ts
@@ -1,4 +1,5 @@
 import { apiClient } from './client';
+import { useAuthStore } from '@/store/authStore';
 import type {
   SendVerificationRequest,
   SendVerificationResponse,
@@ -14,6 +15,10 @@ import type {
   RefreshTokenResponse,
   CheckNicknameRequest,
   CheckNicknameResponse,
+  KakaoLoginRequest,
+  KakaoLoginResponse,
+  KakaoSignupRequest,
+  KakaoSignupResponse,
 } from '@/types/api';
 
 // 회원가입 - 인증번호 발송
@@ -61,10 +66,12 @@ export const login = async (data: LoginRequest): Promise<LoginResponse> => {
   try {
     const response = await apiClient.post<LoginResponse>('/auth/login', data);
     
-    // 💡 안전한 토큰 저장을 위해 분기 처리 유지
-    if (typeof window !== 'undefined' && response.data.data) {
-      localStorage.setItem('accessToken', response.data.data.accessToken);
-      localStorage.setItem('refreshToken', response.data.data.refreshToken);
+    // 전역 상태에 토큰 저장
+    if (response.data.data) {
+      useAuthStore.getState().setTokens(
+        response.data.data.accessToken,
+        response.data.data.refreshToken
+      );
     }
     
     return response.data;
@@ -78,9 +85,13 @@ export const refreshAccessToken = async (data: RefreshTokenRequest): Promise<Ref
   try {
     const response = await apiClient.post<RefreshTokenResponse>('/auth/refresh', data);
     
-    // 💡 재발급 받은 토큰도 다시 저장해줘야 합니다.
-    if (typeof window !== 'undefined' && response.data.data) {
-      localStorage.setItem('accessToken', response.data.data.accessToken);
+    // 재발급 받은 토큰을 전역 상태에 저장
+    if (response.data.data) {
+      const { accessToken, refreshToken: newRefreshToken } = response.data.data;
+      useAuthStore.getState().setTokens(
+        accessToken,
+        newRefreshToken || data.refreshToken // 새 리프레시 토큰이 없으면 기존 것 유지
+      );
     }
     
     return response.data;
@@ -97,4 +108,50 @@ export const checkNickname = async (data: CheckNicknameRequest): Promise<CheckNi
   } catch (error: any) {
     throw error.response?.data || { message: '닉네임 확인에 실패했습니다.' };
   }
+};
+
+// 카카오 로그인
+export const kakaoLogin = async (data: KakaoLoginRequest): Promise<KakaoLoginResponse> => {
+  try {
+    const response = await apiClient.post<KakaoLoginResponse>('/auth/kakao/login', data);
+    
+    // localStorage에 직접 토큰 저장
+    if (response.data.data) {
+      const { accessToken, refreshToken } = response.data.data;
+      
+      if (accessToken && refreshToken) {
+        // localStorage에 직접 저장
+        if (typeof window !== 'undefined') {
+          localStorage.setItem('accessToken', accessToken);
+          localStorage.setItem('refreshToken', refreshToken);
+          
+          // authStore에도 동기화
+          useAuthStore.getState().setTokens(accessToken, refreshToken);
+        }
+      }
+    }
+    
+    return response.data;
+  } catch (error: any) {
+    throw error.response?.data || { message: '카카오 로그인에 실패했습니다.' };
+  }
+};
+
+// 카카오 회원가입
+export const kakaoSignup = async (data: KakaoSignupRequest): Promise<KakaoSignupResponse> => {
+  try {
+    const response = await apiClient.post<KakaoSignupResponse>('/auth/kakao/signup', data);
+    
+    // 전역 상태에 토큰 저장
+    if (response.data.data) {
+      useAuthStore.getState().setTokens(
+        response.data.data.accessToken,
+        response.data.data.refreshToken
+      );
+    }
+    
+    return response.data;
+  } catch (error: any) {
+    throw error.response?.data || { message: '카카오 회원가입에 실패했습니다.' };
+  }
 };
\ No newline at end of file
diff --git a/src/app/(auth)/auth/kakao/callback/page.tsx b/src/app/(auth)/auth/kakao/callback/page.tsx
new file mode 100644
index 0000000..e985d96
--- /dev/null
+++ b/src/app/(auth)/auth/kakao/callback/page.tsx
@@ -0,0 +1,96 @@
+'use client';
+
+import { useEffect, Suspense } from 'react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { kakaoLogin } from '@/api/auth';
+
+function KakaoCallbackContent() {
+  const router = useRouter();
+  const searchParams = useSearchParams();
+
+  useEffect(() => {
+    const handleCallback = async () => {
+      try {
+        // URL에서 code 추출
+        const code = searchParams.get('code');
+        const error = searchParams.get('error');
+
+        // 에러가 있으면 처리
+        if (error) {
+          alert('카카오 로그인에 실패했습니다.');
+          router.push('/');
+          return;
+        }
+
+        // code가 없으면 에러
+        if (!code) {
+          alert('카카오 인증 코드를 받지 못했습니다.');
+          router.push('/');
+          return;
+        }
+
+        // 카카오 로그인 API 호출
+        const response = await kakaoLogin({ code });
+
+        // 신규 가입자면 회원가입으로, 기존 사용자면 홈으로
+        if (response.data?.isNewUser) {
+          // 신규 가입자 - 회원가입 페이지로 kakaoId 전달
+          router.push(`/signup?kakaoId=${response.data.kakaoId}`);
+        } else {
+          // 기존 사용자 - 홈으로 이동
+          router.push('/home');
+        }
+      } catch (error: any) {
+        alert(error.message || '카카오 로그인에 실패했습니다.');
+        router.push('/');
+      }
+    };
+
+    handleCallback();
+  }, [searchParams, router]);
+
+  // 로딩 화면
+  return (
+    <div
+      style={{
+        position: 'fixed',
+        top: 0,
+        left: 0,
+        right: 0,
+        bottom: 0,
+        display: 'flex',
+        justifyContent: 'center',
+        alignItems: 'center',
+        backgroundColor: '#131416',
+      }}
+    >
+      <div style={{ color: '#EAEFF5', fontSize: '16px' }}>카카오 로그인 처리 중...</div>
+    </div>
+  );
+}
+
+export default function KakaoCallbackPage() {
+  return (
+    <Suspense
+      fallback={
+        <div
+          style={{
+            position: 'fixed',
+            top: 0,
+            left: 0,
+            right: 0,
+            bottom: 0,
+            display: 'flex',
+            justifyContent: 'center',
+            alignItems: 'center',
+            backgroundColor: '#131416',
+          }}
+        >
+          <div style={{ color: '#EAEFF5', fontSize: '16px' }}>로딩 중...</div>
+        </div>
+      }
+    >
+      <KakaoCallbackContent />
+    </Suspense>
+  );
+}
diff --git a/src/app/(auth)/signup/page.tsx b/src/app/(auth)/signup/page.tsx
index 39e3bc9..f09e5a8 100644
--- a/src/app/(auth)/signup/page.tsx
+++ b/src/app/(auth)/signup/page.tsx
@@ -1,13 +1,19 @@
 'use client';
 
 import Image from 'next/image';
-import { useState, useEffect } from 'react';
-import { useRouter } from 'next/navigation';
+import { useState, useEffect, Suspense } from 'react';
+import { useRouter, useSearchParams } from 'next/navigation';
 import AuthContainer from '../../(auth)/AuthContainer';
-import { sendVerificationCode, verifyCode, checkNickname } from '@/api/auth';
+import { sendVerificationCode, verifyCode, checkNickname, kakaoSignup } from '@/api/auth';
 
-export default function SignupPage() {
+function SignupPageContent() {
   const router = useRouter();
+  const searchParams = useSearchParams();
+  
+  // 카카오 회원가입 모드 확인
+  const kakaoId = searchParams.get('kakaoId');
+  const isKakaoMode = !!kakaoId;
+  
   const [step, setStep] = useState(1);
   const [name, setName] = useState('');
   const [email, setEmail] = useState('');
@@ -215,7 +221,25 @@ const handleVerifyCode = async () => {
     }
   };
 
-  const handleNext = () => {
+  const handleNext = async () => {
+    // 카카오 모드이고 step 1(닉네임 입력) 완료 시 카카오 회원가입 API 호출
+    if (isKakaoMode && step === 1 && isNicknameChecked) {
+      try {
+        setLoading(true);
+        await kakaoSignup({
+          kakaoId: kakaoId!,
+          nickname: name.trim(),
+        });
+        // 회원가입 성공 시 홈으로 이동
+        router.push('/home');
+      } catch (err: any) {
+        setNicknameError(err.message || '회원가입에 실패했습니다.');
+        setLoading(false);
+      }
+      return;
+    }
+    
+    // 일반 회원가입 플로우
     if (step < 4) {
       setStep(step + 1);
     } else {
@@ -236,6 +260,11 @@ const handleVerifyCode = async () => {
   };
 
   const renderStepContent = () => {
+    // 카카오 모드일 때는 step 1만 보여줌
+    if (isKakaoMode && step !== 1) {
+      return null;
+    }
+    
     switch (step) {
       case 1:
         return (
@@ -951,15 +980,17 @@ const handleVerifyCode = async () => {
 
   return (
     <AuthContainer
-      title="회원가입"
+      title={isKakaoMode ? "카카오 회원가입" : "회원가입"}
       currentStep={step}
-      totalSteps={4}
+      totalSteps={isKakaoMode ? 0 : 4}
       buttonText={
-        step === 2 
-          ? (isCodeSent ? "인증하기" : "인증번호 전송")
-          : step === 4
-            ? "가입하기"
-            : "다음"
+        isKakaoMode && step === 1
+          ? "완료"
+          : step === 2 
+            ? (isCodeSent ? "인증하기" : "인증번호 전송")
+            : step === 4
+              ? "가입하기"
+              : "다음"
       }
       buttonDisabled={
         step === 1 ? (!name || !isNicknameChecked) :
@@ -973,6 +1004,12 @@ const handleVerifyCode = async () => {
         false
       }
       onNext={() => {
+        // 카카오 모드일 때는 step 1에서 바로 회원가입 처리
+        if (isKakaoMode && step === 1) {
+          handleNext();
+          return;
+        }
+        
         if (step === 2) {
           if (!isCodeSent) {
             handleSendVerificationCode();
@@ -996,4 +1033,24 @@ const handleVerifyCode = async () => {
       {renderStepContent()}
     </AuthContainer>
   );
+}
+
+export default function SignupPage() {
+  return (
+    <Suspense fallback={
+      <div className="flex flex-col mx-auto" style={{
+        width: '390px',
+        height: '844px',
+        background: 'var(--color-bg-100, #131416)',
+        position: 'relative',
+        display: 'flex',
+        alignItems: 'center',
+        justifyContent: 'center',
+      }}>
+        <p style={{ color: '#fff' }}>로딩 중...</p>
+      </div>
+    }>
+      <SignupPageContent />
+    </Suspense>
+  );
 }
\ No newline at end of file
diff --git a/src/app/page.tsx b/src/app/page.tsx
index b1f51c2..f59d28e 100644
--- a/src/app/page.tsx
+++ b/src/app/page.tsx
@@ -75,8 +75,22 @@ function LoginSelectScreen() {
 
   const handleKakaoLogin = () => {
     setLoading(true);
-    alert('카카오 로그인 (개발 중)');
-    setLoading(false);
+    
+    // 카카오 OAuth 인증 URL 생성
+    const kakaoClientId = process.env.NEXT_PUBLIC_KAKAO_CLIENT_ID;
+    // 프론트엔드 callback URL 사용
+    const redirectUri = process.env.NEXT_PUBLIC_KAKAO_REDIRECT_URI || 
+      `${window.location.origin}/auth/kakao/callback`;
+    
+    if (!kakaoClientId) {
+      alert('카카오 로그인 설정이 완료되지 않았습니다.');
+      setLoading(false);
+      return;
+    }
+
+    // 카카오 인증 페이지로 리다이렉트
+    const kakaoAuthUrl = `https://kauth.kakao.com/oauth/authorize?client_id=${kakaoClientId}&redirect_uri=${encodeURIComponent(redirectUri)}&response_type=code`;
+    window.location.href = kakaoAuthUrl;
   };
 
   return (
diff --git a/src/store/authStore.ts b/src/store/authStore.ts
new file mode 100644
index 0000000..d17c03e
--- /dev/null
+++ b/src/store/authStore.ts
@@ -0,0 +1,49 @@
+import { create } from 'zustand';
+
+interface AuthState {
+  // 액션
+  setTokens: (accessToken: string, refreshToken: string) => void;
+  clearTokens: () => void;
+  getAccessToken: () => string | null;
+  getRefreshToken: () => string | null;
+  isAuthenticated: () => boolean;
+}
+
+export const useAuthStore = create<AuthState>()((set, get) => ({
+  setTokens: (accessToken: string, refreshToken: string) => {
+    // localStorage에 직접 저장 (페이지 이동 후에도 유지)
+    if (typeof window !== 'undefined') {
+      localStorage.setItem('accessToken', accessToken);
+      localStorage.setItem('refreshToken', refreshToken);
+    }
+  },
+
+  clearTokens: () => {
+    // localStorage에서 삭제
+    if (typeof window !== 'undefined') {
+      localStorage.removeItem('accessToken');
+      localStorage.removeItem('refreshToken');
+    }
+  },
+
+  getAccessToken: () => {
+    if (typeof window !== 'undefined') {
+      return localStorage.getItem('accessToken');
+    }
+    return null;
+  },
+
+  getRefreshToken: () => {
+    if (typeof window !== 'undefined') {
+      return localStorage.getItem('refreshToken');
+    }
+    return null;
+  },
+
+  isAuthenticated: () => {
+    if (typeof window !== 'undefined') {
+      return !!localStorage.getItem('accessToken');
+    }
+    return false;
+  },
+}));
diff --git a/src/types/api.ts b/src/types/api.ts
index a8d880a..3874d07 100644
--- a/src/types/api.ts
+++ b/src/types/api.ts
@@ -76,4 +76,33 @@ export interface CheckNicknameRequest {
 export interface CheckNicknameResponse {
   status: string;
   data: object;
+}
+
+// 카카오 로그인
+export interface KakaoLoginRequest {
+  code: string;
+}
+
+export interface KakaoLoginResponse {
+  status: string;
+  data: {
+    accessToken: string;
+    refreshToken: string;
+    kakaoId: string;
+    isNewUser: boolean;
+  };
+}
+
+// 카카오 회원가입
+export interface KakaoSignupRequest {
+  kakaoId: string;
+  nickname: string;
+}
+
+export interface KakaoSignupResponse {
+  status: string;
+  data: {
+    accessToken: string;
+    refreshToken: string;
+  };
 }
\ No newline at end of file