diff --git a/app/src/main/java/com/kikidan/todakun/TodakunApp.kt b/app/src/main/java/com/kikidan/todakun/TodakunApp.kt
index 901d878f..2b3afbc1 100644
--- a/app/src/main/java/com/kikidan/todakun/TodakunApp.kt
+++ b/app/src/main/java/com/kikidan/todakun/TodakunApp.kt
@@ -145,6 +145,7 @@ fun TodakunApp(
                             onFinish = { navigator.resetTo(TodakunRoute.Home) },
                             onNavigateTerm = { navigator.goBack() },
                             onboardingToken = OnboardingToken(route.onboardingToken),
+                            snackbarHostState = snackbarHostState,
                         )
                     }
 
diff --git a/core/designsystem/src/main/res/values/strings.xml b/core/designsystem/src/main/res/values/strings.xml
index c6051eb1..f7605165 100644
--- a/core/designsystem/src/main/res/values/strings.xml
+++ b/core/designsystem/src/main/res/values/strings.xml
@@ -314,6 +314,8 @@
     <string name="onboarding_next">다음</string>
     <string name="onboarding_start">시작하기</string>
     <string name="onboarding_confirm">확인</string>
+    <string name="onboarding_signup_error">회원가입에 실패했어요. 잠시 후 다시 시도해주세요</string>
+    <string name="onboarding_invalid_input_error">입력한 정보를 다시 확인해주세요.</string>
 
     <!-- 약관 동의 -->
     <string name="onboarding_terms_progress_label">약관 동의</string>
diff --git a/feature/auth/src/main/java/com/kikidan/auth/component/SocialLoginButton.kt b/feature/auth/src/main/java/com/kikidan/auth/component/SocialLoginButton.kt
index a3a4f346..8436459e 100644
--- a/feature/auth/src/main/java/com/kikidan/auth/component/SocialLoginButton.kt
+++ b/feature/auth/src/main/java/com/kikidan/auth/component/SocialLoginButton.kt
@@ -11,6 +11,7 @@ import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.Text
 import androidx.compose.material3.ripple
 import androidx.compose.runtime.Composable
@@ -58,6 +59,7 @@ internal fun SocialLoginButton(
     provider: SocialLoginProvider,
     onClick: () -> Unit,
     modifier: Modifier = Modifier,
+    isLoading: Boolean = false,
 ) {
     Box(
         modifier =
@@ -74,20 +76,28 @@ internal fun SocialLoginButton(
                 ),
         contentAlignment = Alignment.Center,
     ) {
-        Row(
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.spacedBy(8.dp),
-        ) {
-            Image(
-                painter = painterResource(id = provider.iconRes),
-                contentDescription = null,
+        if (isLoading) {
+            CircularProgressIndicator(
                 modifier = Modifier.size(20.dp),
-            )
-            Text(
-                text = stringResource(id = provider.labelRes),
-                style = TodakunTypography.body2Medium,
                 color = provider.contentColor,
+                strokeWidth = 2.dp,
             )
+        } else {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.spacedBy(8.dp),
+            ) {
+                Image(
+                    painter = painterResource(id = provider.iconRes),
+                    contentDescription = null,
+                    modifier = Modifier.size(20.dp),
+                )
+                Text(
+                    text = stringResource(id = provider.labelRes),
+                    style = TodakunTypography.body2Medium,
+                    color = provider.contentColor,
+                )
+            }
         }
     }
 }
diff --git a/feature/auth/src/main/java/com/kikidan/auth/screen/LoginScreen.kt b/feature/auth/src/main/java/com/kikidan/auth/screen/LoginScreen.kt
index a391f07f..4e2259f7 100644
--- a/feature/auth/src/main/java/com/kikidan/auth/screen/LoginScreen.kt
+++ b/feature/auth/src/main/java/com/kikidan/auth/screen/LoginScreen.kt
@@ -13,6 +13,11 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.systemBarsPadding
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.painterResource
@@ -34,6 +39,10 @@ internal fun LoginScreen(
     modifier: Modifier = Modifier,
 ) {
     val loginEnabled = state is LoginState.Idle || state is LoginState.Failure
+    var loadingProvider by remember { mutableStateOf<SocialLoginProvider?>(null) }
+    LaunchedEffect(state) {
+        if (state !is LoginState.Loading) loadingProvider = null
+    }
     Box(
         modifier =
             modifier
@@ -77,8 +86,12 @@ internal fun LoginScreen(
             SocialLoginProvider.entries.forEach { provider ->
                 SocialLoginButton(
                     enabled = loginEnabled,
+                    isLoading = state is LoginState.Loading && loadingProvider == provider,
                     provider = provider,
-                    onClick = { onProviderClick(provider) },
+                    onClick = {
+                        loadingProvider = provider
+                        onProviderClick(provider)
+                    },
                 )
             }
         }
diff --git a/feature/onboarding/src/main/java/com/kikidan/onboarding/OnboardingRoute.kt b/feature/onboarding/src/main/java/com/kikidan/onboarding/OnboardingRoute.kt
index 586058b3..db38745a 100644
--- a/feature/onboarding/src/main/java/com/kikidan/onboarding/OnboardingRoute.kt
+++ b/feature/onboarding/src/main/java/com/kikidan/onboarding/OnboardingRoute.kt
@@ -5,6 +5,7 @@ import android.os.Build
 import androidx.activity.compose.BackHandler
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.material3.SnackbarHostState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
@@ -12,7 +13,9 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
 import androidx.hilt.navigation.compose.hiltViewModel
+import com.kikidan.designsystem.R
 import com.kikidan.designsystem.component.wheelpicker.BirthDateState
 import com.kikidan.designsystem.component.wheelpicker.BirthDateWheelPicker
 import com.kikidan.designsystem.component.wheelpicker.SajuBirthTimeWheelPicker
@@ -34,6 +37,7 @@ fun OnboardingRoute(
     onFinish: () -> Unit,
     onNavigateTerm: () -> Unit,
     onboardingToken: OnboardingToken,
+    snackbarHostState: SnackbarHostState,
     modifier: Modifier = Modifier,
     viewModel: OnboardingViewModel = hiltViewModel(),
 ) {
@@ -48,6 +52,8 @@ fun OnboardingRoute(
             // 권한을 허락하지 않더라도 앱 진입
             permissionHandled = true
         }
+    val signupErrorMessage = stringResource(R.string.onboarding_signup_error)
+    val invalidInputErrorMessage = stringResource(R.string.onboarding_invalid_input_error)
 
     viewModel.collectSideEffect { sideEffect ->
         when (sideEffect) {
@@ -67,7 +73,13 @@ fun OnboardingRoute(
                 }
             }
 
-            else -> { /* TODO 에러 처리 스낵바 또는 다이얼로그 */ }
+            OnboardingSideEffect.InvalidInput -> {
+                snackbarHostState.showSnackbar(invalidInputErrorMessage)
+            }
+
+            is OnboardingSideEffect.Failure -> {
+                snackbarHostState.showSnackbar(signupErrorMessage)
+            }
         }
     }