diff --git a/clang-tools-extra/clangd/CodeComplete.h b/clang-tools-extra/clangd/CodeComplete.h
--- a/clang-tools-extra/clangd/CodeComplete.h
+++ b/clang-tools-extra/clangd/CodeComplete.h
@@ -291,7 +291,7 @@
 // For index-based completion, we only consider:
 //   * symbols in namespaces or translation unit scopes (e.g. no class
 //     members, no locals)
-//   * enum constants in unscoped enum decl (e.g. "red" in "enum {red};")
+//   * enum constants (both scoped and unscoped)
 //   * primary templates (no specializations)
 // For the other cases, we let Clang do the completion because it does not
 // need any non-local information and it will be much better at following
diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
--- a/clang-tools-extra/clangd/CodeComplete.cpp
+++ b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -2129,8 +2129,10 @@
   if (InTopLevelScope(ND))
     return true;
 
+  // Always index enum constants, even if they're not in the top level scope: when
+  // --all-scopes-completion is set, we'll want to complete those as well.
   if (const auto *EnumDecl = dyn_cast<clang::EnumDecl>(ND.getDeclContext()))
-    return InTopLevelScope(*EnumDecl) && !EnumDecl->isScoped();
+    return true;
 
   return false;
 }
diff --git a/clang-tools-extra/clangd/index/Serialization.cpp b/clang-tools-extra/clangd/index/Serialization.cpp
--- a/clang-tools-extra/clangd/index/Serialization.cpp
+++ b/clang-tools-extra/clangd/index/Serialization.cpp
@@ -455,7 +455,7 @@
 // The current versioning scheme is simple - non-current versions are rejected.
 // If you make a breaking change, bump this version number to invalidate stored
 // data. Later we may want to support some backward compatibility.
-constexpr static uint32_t Version = 17;
+constexpr static uint32_t Version = 18;
 
 llvm::Expected<IndexFileIn> readRIFF(llvm::StringRef Data,
                                      SymbolOrigin Origin) {
diff --git a/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp b/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
--- a/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
+++ b/clang-tools-extra/clangd/unittests/SymbolCollectorTests.cpp
@@ -1316,6 +1316,11 @@
       Black
     };
     }
+    class Color3 {
+      enum {
+        Blue
+      };
+    };
   )";
   runSymbolCollector(Header, /*Main=*/"");
   EXPECT_THAT(Symbols,
@@ -1324,7 +1329,9 @@
                   AllOf(qName("Color"), forCodeCompletion(true)),
                   AllOf(qName("Green"), forCodeCompletion(true)),
                   AllOf(qName("Color2"), forCodeCompletion(true)),
-                  AllOf(qName("Color2::Yellow"), forCodeCompletion(false)),
+                  AllOf(qName("Color2::Yellow"), forCodeCompletion(true)),
+                  AllOf(qName("Color3"), forCodeCompletion(true)),
+                  AllOf(qName("Color3::Blue"), forCodeCompletion(true)),
                   AllOf(qName("ns"), forCodeCompletion(true)),
                   AllOf(qName("ns::Black"), forCodeCompletion(true))));
 }