diff --git a/Sources/SourceKitLSP/Swift/DocumentFormatting.swift b/Sources/SourceKitLSP/Swift/DocumentFormatting.swift
index 8296dcd59..872f25422 100644
--- a/Sources/SourceKitLSP/Swift/DocumentFormatting.swift
+++ b/Sources/SourceKitLSP/Swift/DocumentFormatting.swift
@@ -190,6 +190,7 @@ extension SwiftLanguageService {
     var args = try [
       swiftFormat.filePath,
       "format",
+      "-",  // Read file contents from stdin
       "--configuration",
       swiftFormatConfiguration(for: textDocument.uri, options: options),
     ]