diff --git a/core/deployment/src/main/java/io/quarkus/deployment/builditem/SetClassPathSystemPropBuildItem.java b/core/deployment/src/main/java/io/quarkus/deployment/builditem/SetClassPathSystemPropBuildItem.java
new file mode 100644
index 0000000000000..7461e22f7a73f
--- /dev/null
+++ b/core/deployment/src/main/java/io/quarkus/deployment/builditem/SetClassPathSystemPropBuildItem.java
@@ -0,0 +1,12 @@
+package io.quarkus.deployment.builditem;
+
+import io.quarkus.builder.item.MultiBuildItem;
+
+/**
+ * A marker build item to make Quarkus set the {@code java.class.path} system property.
+ * This system property is used in rare by libraries (Truffle for example) to create their own ClassLoaders.
+ * The value of the system property is simply best effort, as there is no way to faithfully represent
+ * the Quarkus ClassLoader hierarchies in a system property value.
+ */
+public final class SetClassPathSystemPropBuildItem extends MultiBuildItem {
+}
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassPathSystemPropBuildStep.java b/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassPathSystemPropBuildStep.java
new file mode 100644
index 0000000000000..feda25cbade14
--- /dev/null
+++ b/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassPathSystemPropBuildStep.java
@@ -0,0 +1,53 @@
+package io.quarkus.deployment.steps;
+
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import io.quarkus.deployment.annotations.BuildProducer;
+import io.quarkus.deployment.annotations.BuildStep;
+import io.quarkus.deployment.annotations.ExecutionTime;
+import io.quarkus.deployment.annotations.Record;
+import io.quarkus.deployment.builditem.SetClassPathSystemPropBuildItem;
+import io.quarkus.deployment.pkg.builditem.CurateOutcomeBuildItem;
+import io.quarkus.maven.dependency.ResolvedDependency;
+import io.quarkus.runtime.ClassPathSystemPropertyRecorder;
+
+public class ClassPathSystemPropBuildStep {
+
+    @BuildStep
+    public void produce(BuildProducer<SetClassPathSystemPropBuildItem> producer, CurateOutcomeBuildItem curateOutcome) {
+        boolean truffleUsed = curateOutcome.getApplicationModel().getDependencies().stream()
+                .anyMatch(d -> d.getGroupId().equals("org.graalvm.polyglot"));
+        if (truffleUsed) {
+            producer.produce(new SetClassPathSystemPropBuildItem());
+        }
+    }
+
+    @BuildStep
+    @Record(ExecutionTime.STATIC_INIT)
+    public void set(List<SetClassPathSystemPropBuildItem> setCPItems,
+            CurateOutcomeBuildItem curateOutcome,
+            ClassPathSystemPropertyRecorder recorder) {
+        if (setCPItems.isEmpty()) {
+            return;
+        }
+        Collection<ResolvedDependency> runtimeDependencies = curateOutcome.getApplicationModel().getRuntimeDependencies();
+        List<Path> parentFirst = new ArrayList<>();
+        List<Path> regular = new ArrayList<>();
+        for (ResolvedDependency dependency : runtimeDependencies) {
+            if (dependency.isClassLoaderParentFirst()) {
+                parentFirst.addAll(dependency.getContentTree().getRoots());
+            } else {
+                regular.addAll(dependency.getContentTree().getRoots());
+
+            }
+        }
+        String classPathValue = Stream.concat(parentFirst.stream(), regular.stream()).map(p -> p.toAbsolutePath().toString())
+                .collect(Collectors.joining(":"));
+        recorder.set(classPathValue);
+    }
+}
diff --git a/core/runtime/src/main/java/io/quarkus/runtime/ClassPathSystemPropertyRecorder.java b/core/runtime/src/main/java/io/quarkus/runtime/ClassPathSystemPropertyRecorder.java
new file mode 100644
index 0000000000000..fdca4fcb0cb65
--- /dev/null
+++ b/core/runtime/src/main/java/io/quarkus/runtime/ClassPathSystemPropertyRecorder.java
@@ -0,0 +1,11 @@
+package io.quarkus.runtime;
+
+import io.quarkus.runtime.annotations.Recorder;
+
+@Recorder
+public class ClassPathSystemPropertyRecorder {
+
+    public void set(String value) {
+        System.setProperty("java.class.path", value);
+    }
+}