diff --git a/gopls/doc/vscode.md b/gopls/doc/vscode.md
index c21c894820..f0aff81245 100644
--- a/gopls/doc/vscode.md
+++ b/gopls/doc/vscode.md
@@ -12,6 +12,12 @@ Use the [VSCode-Go] plugin, with the following configuration:
     // Optional: Disable snippets, as they conflict with completion ranking.
     "editor.snippetSuggestions": "none",
 },
+"[go.mod]": {
+    "editor.formatOnSave": true,
+    "editor.codeActionsOnSave": {
+        "source.organizeImports": true,
+    },
+},
 "gopls": {
      // Add parameter placeholders when completing a function.
     "usePlaceholders": true,
diff --git a/internal/lsp/format.go b/internal/lsp/format.go
index 33dd4072a7..f9bf5aa903 100644
--- a/internal/lsp/format.go
+++ b/internal/lsp/format.go
@@ -7,18 +7,21 @@ package lsp
 import (
 	"context"
 
+	"golang.org/x/tools/internal/lsp/mod"
 	"golang.org/x/tools/internal/lsp/protocol"
 	"golang.org/x/tools/internal/lsp/source"
 )
 
 func (s *Server) formatting(ctx context.Context, params *protocol.DocumentFormattingParams) ([]protocol.TextEdit, error) {
-	snapshot, fh, ok, err := s.beginFileRequest(params.TextDocument.URI, source.Go)
+	snapshot, fh, ok, err := s.beginFileRequest(params.TextDocument.URI, source.UnknownKind)
 	if !ok {
 		return nil, err
 	}
-	edits, err := source.Format(ctx, snapshot, fh)
-	if err != nil {
-		return nil, err
+	switch fh.Identity().Kind {
+	case source.Mod:
+		return mod.Format(ctx, snapshot, fh)
+	case source.Go:
+		return source.Format(ctx, snapshot, fh)
 	}
-	return edits, nil
+	return nil, nil
 }
diff --git a/internal/lsp/mod/format.go b/internal/lsp/mod/format.go
new file mode 100644
index 0000000000..40dfe495f9
--- /dev/null
+++ b/internal/lsp/mod/format.go
@@ -0,0 +1,26 @@
+package mod
+
+import (
+	"context"
+
+	"golang.org/x/tools/internal/lsp/protocol"
+	"golang.org/x/tools/internal/lsp/source"
+	"golang.org/x/tools/internal/telemetry/trace"
+)
+
+func Format(ctx context.Context, snapshot source.Snapshot, fh source.FileHandle) ([]protocol.TextEdit, error) {
+	ctx, done := trace.StartSpan(ctx, "mod.Format")
+	defer done()
+
+	file, m, err := snapshot.ModHandle(ctx, fh).Parse(ctx)
+	if err != nil {
+		return nil, err
+	}
+	formatted, err := file.Format()
+	if err != nil {
+		return nil, err
+	}
+	// Calculate the edits to be made due to the change.
+	diff := snapshot.View().Options().ComputeEdits(fh.Identity().URI, string(m.Content), string(formatted))
+	return source.ToProtocolEdits(m, diff)
+}