diff --git a/api/src/main/java/io/grpc/NameResolverProvider.java b/api/src/main/java/io/grpc/NameResolverProvider.java
index e7cddfc36d0..13cd750c36d 100644
--- a/api/src/main/java/io/grpc/NameResolverProvider.java
+++ b/api/src/main/java/io/grpc/NameResolverProvider.java
@@ -61,6 +61,8 @@ public abstract class NameResolverProvider extends NameResolver.Factory {
    * delegates to {@link Factory#getDefaultScheme()} before {@link NameResolver.Factory} is
    * deprecated in https://github.com/grpc/grpc-java/issues/7133.
    *
+   * <p>The scheme should be lower-case.
+   *
    * @since 1.40.0
    * */
   protected String getScheme() {
diff --git a/api/src/main/java/io/grpc/NameResolverRegistry.java b/api/src/main/java/io/grpc/NameResolverRegistry.java
index ab8a1e803eb..37dd9283297 100644
--- a/api/src/main/java/io/grpc/NameResolverRegistry.java
+++ b/api/src/main/java/io/grpc/NameResolverRegistry.java
@@ -26,6 +26,7 @@
 import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -162,7 +163,11 @@ private final class NameResolverFactory extends NameResolver.Factory {
     @Override
     @Nullable
     public NameResolver newNameResolver(URI targetUri, NameResolver.Args args) {
-      NameResolverProvider provider = providers().get(targetUri.getScheme());
+      String scheme = targetUri.getScheme();
+      if (scheme == null) {
+        return null;
+      }
+      NameResolverProvider provider = providers().get(scheme.toLowerCase(Locale.US));
       return provider == null ? null : provider.newNameResolver(targetUri, args);
     }
 
diff --git a/api/src/test/java/io/grpc/NameResolverRegistryTest.java b/api/src/test/java/io/grpc/NameResolverRegistryTest.java
index 55e43128109..19ae09520dd 100644
--- a/api/src/test/java/io/grpc/NameResolverRegistryTest.java
+++ b/api/src/test/java/io/grpc/NameResolverRegistryTest.java
@@ -183,8 +183,12 @@ public NameResolver newNameResolver(URI passedUri, NameResolver.Args passedArgs)
         });
 
     assertThat(registry.asFactory().newNameResolver(uri, args)).isNull();
+    assertThat(registry.asFactory().newNameResolver(URI.create("/0.0.0.0:80"), args)).isNull();
+    assertThat(registry.asFactory().newNameResolver(URI.create("///0.0.0.0:80"), args)).isNull();
     assertThat(registry.asFactory().newNameResolver(URI.create("other:///0.0.0.0:80"), args))
             .isSameInstanceAs(nr);
+    assertThat(registry.asFactory().newNameResolver(URI.create("OTHER:///0.0.0.0:80"), args))
+            .isSameInstanceAs(nr);
     assertThat(registry.asFactory().getDefaultScheme()).isEqualTo("dns");
   }