diff --git a/README.md b/README.md
index d730fa6..1e850d5 100644
--- a/README.md
+++ b/README.md
@@ -35,6 +35,7 @@ AWS_ACCESS_KEY_ID         | AWS `access key` for API access.                  |
 AWS_SECRET_ACCESS_KEY     | AWS `secret key` for API access.                  |          | EC2 Instance Role
 AWS_API_ENDPOINT          | The endpoint for AWS API for local development.   |          | -
 INDEX_DOCUMENT            | Name of your index document.                      |          | index.html
+INDEX_ON_404              | Serve index document on 404 error                 |          | false
 DIRECTORY_LISTINGS        | List files when a specified URL ends with /.      |          | false
 DIRECTORY_LISTINGS_FORMAT | Configures directory listing to be `html` (spider parsable) |       | -
 HTTP_CACHE_CONTROL        | Overrides S3's HTTP `Cache-Control` header.       |          | S3 Object metadata
diff --git a/docker-compose.yml b/docker-compose.yml
index daed992..463ef0a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -17,6 +17,7 @@ services:
       - AWS_S3_BUCKET
       - AWS_S3_KEY_PREFIX
       - INDEX_DOCUMENT
+      - INDEX_ON_404
       - DIRECTORY_LISTINGS
       - DIRECTORY_LISTINGS_FORMAT
       - HTTP_CACHE_CONTROL
diff --git a/internal/config/config.go b/internal/config/config.go
index 6e80c32..612c340 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -22,6 +22,7 @@ type config struct { // nolint
 	S3Bucket           string        // AWS_S3_BUCKET
 	S3KeyPrefix        string        // AWS_S3_KEY_PREFIX
 	IndexDocument      string        // INDEX_DOCUMENT
+	IndexOn404         bool          // INDEX_ON_404
 	DirectoryListing   bool          // DIRECTORY_LISTINGS
 	DirListingFormat   string        // DIRECTORY_LISTINGS_FORMAT
 	HTTPCacheControl   string        // HTTP_CACHE_CONTROL (max-age=86400, no-cache ...)
@@ -62,6 +63,10 @@ func Setup() {
 	if len(indexDocument) == 0 {
 		indexDocument = "index.html"
 	}
+	indexOn404 := false
+	if b, err := strconv.ParseBool(os.Getenv("INDEX_ON_404")); err == nil {
+		indexOn404 = b
+	}
 	directoryListings := false
 	if b, err := strconv.ParseBool(os.Getenv("DIRECTORY_LISTINGS")); err == nil {
 		directoryListings = b
@@ -104,6 +109,7 @@ func Setup() {
 		S3Bucket:           os.Getenv("AWS_S3_BUCKET"),
 		S3KeyPrefix:        os.Getenv("AWS_S3_KEY_PREFIX"),
 		IndexDocument:      indexDocument,
+		IndexOn404:         indexOn404,
 		DirectoryListing:   directoryListings,
 		DirListingFormat:   os.Getenv("DIRECTORY_LISTINGS_FORMAT"),
 		HTTPCacheControl:   os.Getenv("HTTP_CACHE_CONTROL"),
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index c1cd509..d3aafe8 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -15,6 +15,7 @@ func defaultConfig() *config {
 		S3Bucket:           "",
 		S3KeyPrefix:        "",
 		IndexDocument:      "index.html",
+		IndexOn404:         false,
 		DirectoryListing:   false,
 		DirListingFormat:   "",
 		HTTPCacheControl:   "",
@@ -49,6 +50,7 @@ func TestConfigDefaults(t *testing.T) {
 func TestChangeDefaults(t *testing.T) {
 	os.Setenv("DIRECTORY_LISTINGS", "1")
 	os.Setenv("ACCESS_LOG", "True")
+	os.Setenv("INDEX_ON_404", "True")
 	os.Setenv("CONTENT_ENCODING", "f")
 	os.Setenv("CORS_MAX_AGE", "0")
 	os.Setenv("GET_ALL_PAGES_IN_DIR", "TRUE")
@@ -62,6 +64,7 @@ func TestChangeDefaults(t *testing.T) {
 	expected := defaultConfig()
 	expected.DirectoryListing = true
 	expected.AccessLog = true
+	expected.IndexOn404 = true
 	expected.ContentEncoding = false
 	expected.CorsMaxAge = 0
 	expected.AllPagesInDir = true
diff --git a/internal/controllers/s3.go b/internal/controllers/s3.go
index 7243e7c..a613623 100644
--- a/internal/controllers/s3.go
+++ b/internal/controllers/s3.go
@@ -67,8 +67,17 @@ func AwsS3(w http.ResponseWriter, r *http.Request) {
 	obj, err := client.S3get(c.S3Bucket, c.S3KeyPrefix+path, rangeHeader)
 	if err != nil {
 		code, message := toHTTPError(err)
-		http.Error(w, message, code)
-		return
+		if code == 404 && c.IndexOn404 {
+			obj, err = client.S3get(c.S3Bucket, c.S3KeyPrefix+c.IndexDocument, rangeHeader)
+			if err != nil {
+				code, message = toHTTPError(err)
+				http.Error(w, message, code)
+				return
+			}
+		} else {
+			http.Error(w, message, code)
+			return
+		}
 	}
 	setHeadersFromAwsResponse(w, obj, c.HTTPCacheControl, c.HTTPExpires)