diff --git a/libs/ardour/audiofilesource.cc b/libs/ardour/audiofilesource.cc
index b5cb4c7c02..004e93ebda 100644
--- a/libs/ardour/audiofilesource.cc
+++ b/libs/ardour/audiofilesource.cc
@@ -335,6 +335,7 @@ AudioFileSource::safe_audio_file_extension(const string& file)
 		".smp", ".SMP",
 		".snd", ".SND",
 		".maud", ".MAUD",
+		".opus", ".OPUS",
 		".voc", ".VOC",
 		".vwe", ".VWE",
 		".w64", ".W64",