diff --git a/README.md b/README.md
index 6b5047c..6730293 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,18 @@ To print the directory structure of a specific folder:
 printlayout -dir /path/to/your/folder
 ```
 
+To print the directory structure and filter by a specific file extension (e.g., .go, .js, .rb):
+
+```bash
+printlayout -ext .js
+```
+
+To print the directory structure of a specific folder, filter by a specific file extension, and save the output to a file:
+
+```bash
+printlayout -dir /path/to/your/folder -ext .rb -output output.txt
+```
+
 ### Example Output
 
 ```bash
@@ -81,13 +93,7 @@ printLayout/
 To run the project during development without installing it:
 
 ```bash
-go run ./cmd/main.go /path/to/your/folder
-```
-
-### Run the project and export the output to a file
-
-```bash
-go run ./cmd/main.go -dir /path/to/your/folder -output /path/to/output/file
+go run ./cmd/main.go
 ```
 
 ### Run Tests
diff --git a/cmd/main.go b/cmd/main.go
index 31df782..e39773f 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -10,8 +10,9 @@ func main() {
 
 	flag.StringVar(&config.DirPath, "dir", ".", "Directory path to print the structure of")
 	flag.StringVar(&config.OutputPath, "output", "", "Output file path")
+	flag.StringVar(&config.ExtFilter, "ext", "", "File extension filter (e.g., .go, .js)")
 
 	flag.Parse()
 
-	printer.PrintProjectStructure(config.DirPath, config.OutputPath)
+	printer.PrintProjectStructure(config.DirPath, config.OutputPath, config.ExtFilter)
 }
diff --git a/pkg/printer/printer.go b/pkg/printer/printer.go
index 6a32a50..803e30c 100644
--- a/pkg/printer/printer.go
+++ b/pkg/printer/printer.go
@@ -12,16 +12,17 @@ import (
 type Config struct {
 	DirPath    string
 	OutputPath string
+	ExtFilter  string
 }
 
 // HandleFlags
 func HandleFlags(config Config) {
-	PrintProjectStructure(config.DirPath, config.OutputPath)
+	PrintProjectStructure(config.DirPath, config.OutputPath, config.ExtFilter)
 }
 
 // PrintProjectStructure prints the directory structure of the given root directory.
 // It always prints the structure to the console and writes to the output file if provided.
-func PrintProjectStructure(root string, outputFile string) {
+func PrintProjectStructure(root string, outputFile string, extFilter string) {
 	absRoot, err := filepath.Abs(root)
 	if err != nil {
 		fmt.Println("Error getting absolute path:", err)
@@ -30,7 +31,7 @@ func PrintProjectStructure(root string, outputFile string) {
 
 	rootName := filepath.Base(absRoot)
 	output := fmt.Sprintf("%s/\n", rootName)
-	output += getTreeOutput(absRoot, "")
+	output += getTreeOutput(absRoot, "", extFilter)
 
 	fmt.Print(output)
 
@@ -53,7 +54,7 @@ func writeToFile(output, outputFile string) {
 }
 
 // getTreeOutput returns the directory tree structure as a string.
-func getTreeOutput(currentDir string, prefix string) string {
+func getTreeOutput(currentDir string, prefix string, extFilter string) string {
 	var output string
 
 	dir, err := os.Open(currentDir)
@@ -81,9 +82,11 @@ func getTreeOutput(currentDir string, prefix string) string {
 
 		if entry.IsDir() {
 			output += fmt.Sprintf("%s%s/\n", prefix+getTreePrefix(isLast), entry.Name())
-			output += getTreeOutput(filepath.Join(currentDir, entry.Name()), prefix+getIndent(isLast))
+			output += getTreeOutput(filepath.Join(currentDir, entry.Name()), prefix+getIndent(isLast), extFilter)
 		} else {
-			output += fmt.Sprintf("%s%s\n", prefix+getTreePrefix(isLast), entry.Name())
+			if extFilter == "" || strings.HasSuffix(entry.Name(), extFilter) {
+				output += fmt.Sprintf("%s%s\n", prefix+getTreePrefix(isLast), entry.Name())
+			}
 		}
 	}
 
diff --git a/pkg/printer/printer_test.go b/pkg/printer/printer_test.go
index 8d1f385..0dadb95 100644
--- a/pkg/printer/printer_test.go
+++ b/pkg/printer/printer_test.go
@@ -22,7 +22,7 @@ func TestPrintProjectStructure(t *testing.T) {
 	os.Chdir(tmpDir)
 
 	output := captureOutput(func() {
-		PrintProjectStructure(".", "")
+		PrintProjectStructure(".", "", "")
 	})
 
 	rootName := filepath.Base(tmpDir)