diff --git a/image/DecoderFactory.cpp b/image/DecoderFactory.cpp
index 9c46bd1d4828..8320297c2624 100644
--- a/image/DecoderFactory.cpp
+++ b/image/DecoderFactory.cpp
@@ -34,8 +34,6 @@ DecoderFactory::GetDecoderType(const char* aMimeType)
type = DecoderType::PNG;
} else if (!strcmp(aMimeType, IMAGE_X_PNG)) {
type = DecoderType::PNG;
- } else if (!strcmp(aMimeType, IMAGE_APNG)) {
- type = DecoderType::PNG;
// GIF
} else if (!strcmp(aMimeType, IMAGE_GIF)) {
diff --git a/image/build/nsImageModule.cpp b/image/build/nsImageModule.cpp
index 046543845778..5043758a4154 100644
--- a/image/build/nsImageModule.cpp
+++ b/image/build/nsImageModule.cpp
@@ -78,7 +78,6 @@ static const mozilla::Module::CategoryEntry kImageCategories[] = {
{ "Gecko-Content-Viewers", IMAGE_BMP_MS, "@mozilla.org/content/document-loader-factory;1" },
{ "Gecko-Content-Viewers", IMAGE_ICON_MS, "@mozilla.org/content/document-loader-factory;1" },
{ "Gecko-Content-Viewers", IMAGE_PNG, "@mozilla.org/content/document-loader-factory;1" },
- { "Gecko-Content-Viewers", IMAGE_APNG, "@mozilla.org/content/document-loader-factory;1" },
{ "Gecko-Content-Viewers", IMAGE_X_PNG, "@mozilla.org/content/document-loader-factory;1" },
{ "content-sniffing-services", "@mozilla.org/image/loader;1", "@mozilla.org/image/loader;1" },
{ nullptr }
diff --git a/layout/reftests/apng-mime/animated.apng b/layout/reftests/apng-mime/animated.apng
deleted file mode 100644
index a310055bb899..000000000000
Binary files a/layout/reftests/apng-mime/animated.apng and /dev/null differ
diff --git a/layout/reftests/apng-mime/expected.html b/layout/reftests/apng-mime/expected.html
deleted file mode 100644
index d069957fdf67..000000000000
--- a/layout/reftests/apng-mime/expected.html
+++ /dev/null
@@ -1,3 +0,0 @@
-
-apng expected
-
diff --git a/layout/reftests/apng-mime/reftest.list b/layout/reftests/apng-mime/reftest.list
deleted file mode 100644
index fef0f4a7364d..000000000000
--- a/layout/reftests/apng-mime/reftest.list
+++ /dev/null
@@ -1 +0,0 @@
-== test.html expected.html
diff --git a/layout/reftests/apng-mime/static.png b/layout/reftests/apng-mime/static.png
deleted file mode 100644
index 6f76d4438724..000000000000
Binary files a/layout/reftests/apng-mime/static.png and /dev/null differ
diff --git a/layout/reftests/apng-mime/test.html b/layout/reftests/apng-mime/test.html
deleted file mode 100644
index cdf44b901a2e..000000000000
--- a/layout/reftests/apng-mime/test.html
+++ /dev/null
@@ -1,6 +0,0 @@
-
-apng test
-
-
-
-
diff --git a/layout/reftests/reftest.list b/layout/reftests/reftest.list
index 4207909faa8c..b69523c1280b 100644
--- a/layout/reftests/reftest.list
+++ b/layout/reftests/reftest.list
@@ -19,9 +19,6 @@ include w3c-css/received/reftest.list
include abs-pos/reftest.list
include position-relative/reftest.list
-# apng-mime
-include apng-mime/reftest.list
-
include async-scrolling/reftest.list
# backgrounds/
diff --git a/netwerk/mime/nsMimeTypes.h b/netwerk/mime/nsMimeTypes.h
index c5c8855e9bf7..c10f02024ab2 100644
--- a/netwerk/mime/nsMimeTypes.h
+++ b/netwerk/mime/nsMimeTypes.h
@@ -95,7 +95,6 @@
#define IMAGE_JPG "image/jpg"
#define IMAGE_PJPEG "image/pjpeg"
#define IMAGE_PNG "image/png"
-#define IMAGE_APNG "image/apng"
#define IMAGE_X_PNG "image/x-png"
#define IMAGE_PPM "image/x-portable-pixmap"
#define IMAGE_XBM "image/x-xbitmap"
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index f09e4f196213..2ae77abcaa26 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -581,7 +581,6 @@ static const nsExtraMimeTypeEntry extraMimeEntries[] =
{ IMAGE_ICO, "ico,cur", "ICO Image" },
{ IMAGE_JPEG, "jpeg,jpg,jfif,pjpeg,pjp", "JPEG Image" },
{ IMAGE_PNG, "png", "PNG Image" },
- { IMAGE_APNG, "apng", "APNG Image" },
{ IMAGE_TIFF, "tiff,tif", "TIFF Image" },
{ IMAGE_XBM, "xbm", "XBM Image" },
{ IMAGE_SVG_XML, "svg", "Scalable Vector Graphics" },