diff --git a/GCDWebServer/Core/GCDWebServerFunctions.h b/GCDWebServer/Core/GCDWebServerFunctions.h
index 0752bce..4235ecc 100644
--- a/GCDWebServer/Core/GCDWebServerFunctions.h
+++ b/GCDWebServer/Core/GCDWebServerFunctions.h
@@ -36,8 +36,12 @@ extern "C" {
 /**
  *  Converts a file extension to the corresponding MIME type.
  *  If there is no match, "application/octet-stream" is returned.
+ *
+ *  Overrides allow to customize the built-in mapping from extensions to MIME
+ *  types. Keys of the dictionary must be lowercased file extensions without
+ *  the period, and the values must be the corresponding MIME types.
  */
-NSString* GCDWebServerGetMimeTypeForExtension(NSString* extension);
+NSString* GCDWebServerGetMimeTypeForExtension(NSString* extension, NSDictionary* _Nullable overrides);
 
 /**
  *  Add percent-escapes to a string so it can be used in a URL.
diff --git a/GCDWebServer/Core/GCDWebServerFunctions.m b/GCDWebServer/Core/GCDWebServerFunctions.m
index 7c72e34..ec50086 100644
--- a/GCDWebServer/Core/GCDWebServerFunctions.m
+++ b/GCDWebServer/Core/GCDWebServerFunctions.m
@@ -166,12 +166,15 @@ NSString* GCDWebServerDescribeData(NSData* data, NSString* type) {
   return [NSString stringWithFormat:@"<%lu bytes>", (unsigned long)data.length];
 }
 
-NSString* GCDWebServerGetMimeTypeForExtension(NSString* extension) {
-  NSDictionary* overrides = @{@"css": @"text/css"};
+NSString* GCDWebServerGetMimeTypeForExtension(NSString* extension, NSDictionary* overrides) {
+  NSDictionary* builtInOverrides = @{@"css": @"text/css"};
   NSString* mimeType = nil;
   extension = [extension lowercaseString];
   if (extension.length) {
     mimeType = [overrides objectForKey:extension];
+    if (mimeType == nil) {
+      mimeType = [builtInOverrides objectForKey:extension];
+    }
     if (mimeType == nil) {
       CFStringRef uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, (__bridge CFStringRef)extension, NULL);
       if (uti) {
diff --git a/GCDWebServer/Responses/GCDWebServerFileResponse.h b/GCDWebServer/Responses/GCDWebServerFileResponse.h
index f7dbd47..9403835 100644
--- a/GCDWebServer/Responses/GCDWebServerFileResponse.h
+++ b/GCDWebServer/Responses/GCDWebServerFileResponse.h
@@ -95,8 +95,13 @@ NS_ASSUME_NONNULL_BEGIN
 
 /**
  *  This method is the designated initializer for the class.
+ *
+ *  If MIME type overrides are specified, they allow to customize the built-in
+ *  mapping from extensions to MIME types. Keys of the dictionary must be lowercased
+ *  file extensions without the period, and the values must be the corresponding
+ *  MIME types.
  */
-- (nullable instancetype)initWithFile:(NSString*)path byteRange:(NSRange)range isAttachment:(BOOL)attachment;
+- (nullable instancetype)initWithFile:(NSString*)path byteRange:(NSRange)range isAttachment:(BOOL)attachment mimeTypeOverrides:(nullable NSDictionary*)overrides;
 
 @end
 
diff --git a/GCDWebServer/Responses/GCDWebServerFileResponse.m b/GCDWebServer/Responses/GCDWebServerFileResponse.m
index f693e1b..bd07518 100644
--- a/GCDWebServer/Responses/GCDWebServerFileResponse.m
+++ b/GCDWebServer/Responses/GCDWebServerFileResponse.m
@@ -57,26 +57,26 @@
 }
 
 + (instancetype)responseWithFile:(NSString*)path byteRange:(NSRange)range isAttachment:(BOOL)attachment {
-  return [[[self class] alloc] initWithFile:path byteRange:range isAttachment:attachment];
+  return [[[self class] alloc] initWithFile:path byteRange:range isAttachment:attachment mimeTypeOverrides:nil];
 }
 
 - (instancetype)initWithFile:(NSString*)path {
-  return [self initWithFile:path byteRange:NSMakeRange(NSUIntegerMax, 0) isAttachment:NO];
+  return [self initWithFile:path byteRange:NSMakeRange(NSUIntegerMax, 0) isAttachment:NO mimeTypeOverrides:nil];
 }
 
 - (instancetype)initWithFile:(NSString*)path isAttachment:(BOOL)attachment {
-  return [self initWithFile:path byteRange:NSMakeRange(NSUIntegerMax, 0) isAttachment:attachment];
+  return [self initWithFile:path byteRange:NSMakeRange(NSUIntegerMax, 0) isAttachment:attachment mimeTypeOverrides:nil];
 }
 
 - (instancetype)initWithFile:(NSString*)path byteRange:(NSRange)range {
-  return [self initWithFile:path byteRange:range isAttachment:NO];
+  return [self initWithFile:path byteRange:range isAttachment:NO mimeTypeOverrides:nil];
 }
 
 static inline NSDate* _NSDateFromTimeSpec(const struct timespec* t) {
   return [NSDate dateWithTimeIntervalSince1970:((NSTimeInterval)t->tv_sec + (NSTimeInterval)t->tv_nsec / 1000000000.0)];
 }
 
-- (instancetype)initWithFile:(NSString*)path byteRange:(NSRange)range isAttachment:(BOOL)attachment {
+- (instancetype)initWithFile:(NSString*)path byteRange:(NSRange)range isAttachment:(BOOL)attachment mimeTypeOverrides:(NSDictionary*)overrides {
   struct stat info;
   if (lstat([path fileSystemRepresentation], &info) || !(info.st_mode & S_IFREG)) {
     GWS_DNOT_REACHED();
@@ -129,7 +129,7 @@ static inline NSDate* _NSDateFromTimeSpec(const struct timespec* t) {
       }
     }
 
-    self.contentType = GCDWebServerGetMimeTypeForExtension([_path pathExtension]);
+    self.contentType = GCDWebServerGetMimeTypeForExtension([_path pathExtension], overrides);
     self.contentLength = _size;
     self.lastModifiedDate = _NSDateFromTimeSpec(&info.st_mtimespec);
     self.eTag = [NSString stringWithFormat:@"%llu/%li/%li", info.st_ino, info.st_mtimespec.tv_sec, info.st_mtimespec.tv_nsec];