diff --git a/errgoengine.go b/errgoengine.go
index 4c645e8..80c5f6c 100644
--- a/errgoengine.go
+++ b/errgoengine.go
@@ -200,6 +200,11 @@ func ParseFiles(contextData *ContextData, defaultLanguage *Language, files fs.Re
 		// check if document already exists
 		existingDoc, docExists := contextData.Documents[path]
 
+		if docExists && existingDoc.BytesContentEquals(contents) {
+			// do not parse if content is the same
+			continue
+		}
+
 		// check matched languages
 		selectedLanguage := defaultLanguage
 		if docExists {
diff --git a/source.go b/source.go
index d7f0754..0569a3a 100644
--- a/source.go
+++ b/source.go
@@ -504,6 +504,14 @@ type Document struct {
 	Tree        *sitter.Tree
 }
 
+func (doc *Document) StringContentEquals(str string) bool {
+	return doc.Contents == str
+}
+
+func (doc *Document) BytesContentEquals(cnt []byte) bool {
+	return doc.Contents == string(cnt)
+}
+
 func (doc *Document) RootNode() SyntaxNode {
 	return WrapNode(doc, doc.Tree.RootNode())
 }