diff --git a/buildSrc/src/main/kotlin/JvmToolchain.kt b/buildSrc/src/main/kotlin/JvmToolchain.kt
index 7a2be70f8e9..9f0fd3e115a 100644
--- a/buildSrc/src/main/kotlin/JvmToolchain.kt
+++ b/buildSrc/src/main/kotlin/JvmToolchain.kt
@@ -23,7 +23,8 @@ enum class JdkMajorVersion(
     JDK_10_0(10, mandatory = false, overrideMajorVersion = 11),
     JDK_11_0(11, mandatory = false),
     JDK_16_0(16, mandatory = false),
-    JDK_17_0(17, mandatory = false);
+    JDK_17_0(17, mandatory = false),
+    JDK_21_0(21, mandatory = false);
 
     fun isMandatory(): Boolean = mandatory
 
diff --git a/compiler/fir/analysis-tests/build.gradle.kts b/compiler/fir/analysis-tests/build.gradle.kts
index 91ce9a9a6c7..999058ac095 100644
--- a/compiler/fir/analysis-tests/build.gradle.kts
+++ b/compiler/fir/analysis-tests/build.gradle.kts
@@ -83,6 +83,9 @@ projectTest(
 projectTest(
     "jdk21Tests",
     jUnitMode = JUnitMode.JUnit5,
+    defineJDKEnvVariables = listOf(
+        JdkMajorVersion.JDK_21_0
+    )
 ) {
     configureTest {
         includeTags("Jdk21Test")
diff --git a/compiler/tests-common-new/build.gradle.kts b/compiler/tests-common-new/build.gradle.kts
index dd8b2b6c742..aa0aba308e1 100644
--- a/compiler/tests-common-new/build.gradle.kts
+++ b/compiler/tests-common-new/build.gradle.kts
@@ -72,6 +72,9 @@ projectTest(
 projectTest(
     "jdk21Tests",
     jUnitMode = JUnitMode.JUnit5,
+    defineJDKEnvVariables = listOf(
+        JdkMajorVersion.JDK_21_0
+    )
 ) {
     configureTest {
         includeTags("Jdk21Test")