diff --git a/test/SourceKit/Diagnostics/remarks.swift b/test/SourceKit/Diagnostics/remarks.swift
new file mode 100644
index 0000000000000..f4febb0dd772a
--- /dev/null
+++ b/test/SourceKit/Diagnostics/remarks.swift
@@ -0,0 +1,15 @@
+// RUN: env %sourcekitd-test -req=diags %s -- %s -Xfrontend -Rmodule-api-import | %FileCheck %s
+public typealias Foo = String
+
+// CHECK:      {
+// CHECK-NEXT:   key.diagnostics: [
+// CHECK-NEXT:   {
+// CHECK-NEXT:       key.line: 2,
+// CHECK-NEXT:       key.column: 24,
+// CHECK-NEXT:       key.filepath: "{{.*}}",
+// CHECK-NEXT:       key.severity: source.diagnostic.severity.remark,
+// CHECK-NEXT:       key.id: "module_api_import",
+// CHECK-NEXT:       key.description: "struct 'String' is imported via 'Swift'"
+// CHECK-NEXT:   }
+// CHECK-NEXT:   ]
+// CHECK-NEXT: }
diff --git a/tools/SourceKit/include/SourceKit/Core/LangSupport.h b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
index 4aa616c391394..98d8d7d453df4 100644
--- a/tools/SourceKit/include/SourceKit/Core/LangSupport.h
+++ b/tools/SourceKit/include/SourceKit/Core/LangSupport.h
@@ -213,7 +213,8 @@ struct FilterRule {
 
 enum class DiagnosticSeverityKind {
   Warning,
-  Error
+  Error,
+  Remark
 };
 
 enum class DiagnosticCategory {
diff --git a/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp b/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp
index d9cae79b0f1c9..d0e675693f3ba 100644
--- a/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp
+++ b/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp
@@ -147,19 +147,12 @@ void EditorDiagConsumer::handleDiagnostic(SourceManager &SM,
   if (Info.ID == diag::lex_editor_placeholder.ID ||
       Info.ID == diag::oslog_invalid_log_message.ID)
     return;
-
   bool IsNote = (Info.Kind == DiagnosticKind::Note);
 
   if (IsNote && !haveLastDiag())
     // Is this possible?
     return;
 
-  if (Info.Kind == DiagnosticKind::Remark) {
-    // FIXME: we may want to handle optimization remarks in sourcekitd.
-    LOG_WARN_FUNC("unhandled optimization remark");
-    return;
-  }
-
   DiagnosticEntryInfo SKInfo;
 
   SKInfo.ID = DiagnosticEngine::diagnosticIDStringFor(Info.ID).str();
@@ -237,7 +230,6 @@ void EditorDiagConsumer::handleDiagnostic(SourceManager &SM,
     getLastDiag().Notes.push_back(std::move(SKInfo));
     return;
   }
-
   switch (Info.Kind) {
   case DiagnosticKind::Error:
     SKInfo.Severity = DiagnosticSeverityKind::Error;
@@ -245,8 +237,10 @@ void EditorDiagConsumer::handleDiagnostic(SourceManager &SM,
   case DiagnosticKind::Warning:
     SKInfo.Severity = DiagnosticSeverityKind::Warning;
     break;
-  case DiagnosticKind::Note:
   case DiagnosticKind::Remark:
+    SKInfo.Severity = DiagnosticSeverityKind::Remark;
+    break;
+  case DiagnosticKind::Note:
     llvm_unreachable("already covered");
   }
 
diff --git a/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp b/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
index fca57f07de4da..ee09af90cfd36 100644
--- a/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
+++ b/tools/SourceKit/tools/sourcekitd/lib/Service/Requests.cpp
@@ -4057,6 +4057,7 @@ fillDictionaryForDiagnosticInfo(ResponseBuilder::Dictionary Elem,
   UIdent SeverityUID;
   static UIdent UIDKindDiagWarning(KindDiagWarning.str());
   static UIdent UIDKindDiagError(KindDiagError.str());
+  static UIdent UIDKindDiagRemark(KindDiagRemark.str());
   switch (Info.Severity) {
   case DiagnosticSeverityKind::Warning:
     SeverityUID = UIDKindDiagWarning;
@@ -4064,6 +4065,9 @@ fillDictionaryForDiagnosticInfo(ResponseBuilder::Dictionary Elem,
   case DiagnosticSeverityKind::Error:
     SeverityUID = UIDKindDiagError;
     break;
+  case DiagnosticSeverityKind::Remark:
+    SeverityUID = UIDKindDiagRemark;
+    break;
   }
 
   Elem.set(KeySeverity, SeverityUID);
diff --git a/utils/gyb_sourcekit_support/UIDs.py b/utils/gyb_sourcekit_support/UIDs.py
index aef3292a9f917..ee13797b50c85 100644
--- a/utils/gyb_sourcekit_support/UIDs.py
+++ b/utils/gyb_sourcekit_support/UIDs.py
@@ -477,6 +477,7 @@ def __init__(self, internal_name, external_name):
     KIND('DiagNote', 'source.diagnostic.severity.note'),
     KIND('DiagWarning', 'source.diagnostic.severity.warning'),
     KIND('DiagError', 'source.diagnostic.severity.error'),
+    KIND('DiagRemark', 'source.diagnostic.severity.remark'),
     KIND('DiagDeprecation', 'source.diagnostic.category.deprecation'),
     KIND('DiagNoUsage', 'source.diagnostic.category.no_usage'),
     KIND('CodeCompletionEverything', 'source.codecompletion.everything'),