diff --git a/Dockerfile b/Dockerfile
index 215970a..cf64814 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 
 # --- Build stage ---
-FROM gradle:8.11.1-jdk17 AS build
+FROM eclipse-temurin:21-jdk AS build
 WORKDIR /app
 
 # 루트 프로젝트 전체 복사
@@ -18,7 +18,7 @@ RUN ./gradlew clean bootJar -x test --no-daemon
 RUN cp "$(ls build/libs/*.jar | head -n 1)" build/libs/app.jar
 
 # --- Runtime stage ---
-FROM eclipse-temurin:17-jre
+FROM eclipse-temurin:21-jre
 WORKDIR /app
 
 COPY --from=build /app/build/libs/app.jar app.jar
diff --git a/build.gradle b/build.gradle
index 2a1615c..6822e0b 100644
--- a/build.gradle
+++ b/build.gradle
@@ -10,7 +10,7 @@ version = '0.0.1-SNAPSHOT'
 
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(25)
+        languageVersion = JavaLanguageVersion.of(21)
     }
 }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 2e11132..e2847c8 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.1.0-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME