diff --git a/javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/ReferenceMatcher.java b/javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/ReferenceMatcher.java
index 98a19b8c05..cf07e9c552 100644
--- a/javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/ReferenceMatcher.java
+++ b/javaagent-tooling/src/main/java/io/opentelemetry/javaagent/tooling/muzzle/matcher/ReferenceMatcher.java
@@ -119,10 +119,6 @@ public final class ReferenceMatcher {
         }
         // helper classes get their own check: whether they implement all abstract methods
         return checkHelperClassMatch(reference, typePool);
-      } else if (helperClassNames.contains(reference.getClassName())) {
-        // skip muzzle check for those helper classes that are not in instrumentation packages; e.g.
-        // some instrumentations inject guava types as helper classes
-        return emptyList();
       } else {
         TypePool.Resolution resolution = typePool.describe(reference.getClassName());
         if (!resolution.isResolved()) {
diff --git a/testing-common/src/test/groovy/muzzle/ReferenceMatcherTest.groovy b/testing-common/src/test/groovy/muzzle/ReferenceMatcherTest.groovy
index a23e3af8f7..300112cfa9 100644
--- a/testing-common/src/test/groovy/muzzle/ReferenceMatcherTest.groovy
+++ b/testing-common/src/test/groovy/muzzle/ReferenceMatcherTest.groovy
@@ -167,20 +167,6 @@ class ReferenceMatcherTest extends Specification {
     "staticB"        | Type.getType(MethodBodyAdvice.B).getDescriptor() | [STATIC, PROTECTED_OR_HIGHER] | MethodBodyAdvice.A  | []                 | "match static field"
   }
 
-  def "should ignore helper classes from third-party packages"() {
-    given:
-    def emptyClassLoader = new URLClassLoader(new URL[0], (ClassLoader) null)
-    def reference = new Reference.Builder("com.google.common.base.Strings")
-      .build()
-
-    when:
-    def mismatches = createMatcher([reference], [reference.className])
-      .getMismatchedReferenceSources(emptyClassLoader)
-
-    then:
-    mismatches.empty
-  }
-
   def "should not check abstract #desc helper classes"() {
     given:
     def reference = new Reference.Builder(className)