diff --git a/dom/media/omx/MediaCodecProxy.cpp b/dom/media/omx/MediaCodecProxy.cpp
index f0d3bcf78121..85287fc0fbba 100644
--- a/dom/media/omx/MediaCodecProxy.cpp
+++ b/dom/media/omx/MediaCodecProxy.cpp
@@ -182,7 +182,7 @@ MediaCodecProxy::releaseCodec()
 
     // Release MediaCodec
     if (mCodec != nullptr) {
-      status_t err = mCodec->stop();
+      mCodec->stop();
       mCodec->release();
       mCodec = nullptr;
     }
@@ -493,7 +493,6 @@ MediaCodecProxy::resourceCanceled()
 bool MediaCodecProxy::Prepare()
 {
 
-  status_t err;
   if (start() != OK) {
     MCP_LOG("Couldn't start MediaCodec");
     return false;
diff --git a/dom/media/omx/OMXCodecDescriptorUtil.cpp b/dom/media/omx/OMXCodecDescriptorUtil.cpp
index 09490c3b71e9..2382f2c29381 100644
--- a/dom/media/omx/OMXCodecDescriptorUtil.cpp
+++ b/dom/media/omx/OMXCodecDescriptorUtil.cpp
@@ -189,7 +189,6 @@ GenerateAVCDescriptorBlob(sp<AMessage>& aConfigData,
     return ERROR_MALFORMED;
   }
 
-  status_t result = OK;
   if (aFormat == OMXVideoEncoder::BlobFormat::AVC_NAL) {
     // SPS + PPS.
     aOutputBuf->AppendElements(sps->data(), sps->size());
diff --git a/dom/media/omx/OmxDecoder.cpp b/dom/media/omx/OmxDecoder.cpp
index 70258baa0dea..9a6e6d9175c2 100644
--- a/dom/media/omx/OmxDecoder.cpp
+++ b/dom/media/omx/OmxDecoder.cpp
@@ -118,7 +118,6 @@ bool OmxDecoder::Init(sp<MediaExtractor>& extractor) {
   }
 #endif
 
-  const char* extractorMime;
   sp<MetaData> meta = extractor->getMetaData();
 
   ssize_t audioTrackIndex = -1;
@@ -176,7 +175,6 @@ bool OmxDecoder::EnsureMetadata() {
   }
   if (mAudioTrack.get()) {
     durationUs = -1;
-    const char* audioMime;
     sp<MetaData> meta = mAudioTrack->getFormat();
 
     if ((durationUs == -1) && meta->findInt64(kKeyDuration, &durationUs)) {
diff --git a/dom/system/gonk/VolumeManager.cpp b/dom/system/gonk/VolumeManager.cpp
index 68ba0f8245bf..857a8e4b7ca3 100644
--- a/dom/system/gonk/VolumeManager.cpp
+++ b/dom/system/gonk/VolumeManager.cpp
@@ -180,7 +180,6 @@ void VolumeManager::InitConfig()
     return;
   }
   while(fgets(line, sizeof(line), fp)) {
-    const char *delim = " \t\n";
     n++;
 
     if (line[0] == '#')
diff --git a/gfx/layers/opengl/GrallocTextureHost.cpp b/gfx/layers/opengl/GrallocTextureHost.cpp
index 849205ef7486..e6e80a0eb0be 100644
--- a/gfx/layers/opengl/GrallocTextureHost.cpp
+++ b/gfx/layers/opengl/GrallocTextureHost.cpp
@@ -231,7 +231,7 @@ TemporaryRef<gfx::DataSourceSurface>
 GrallocTextureHostOGL::GetAsSurface() {
   android::GraphicBuffer* graphicBuffer = GetGraphicBufferFromDesc(mGrallocHandle).get();
   uint8_t* grallocData;
-  int32_t rv = graphicBuffer->lock(GRALLOC_USAGE_SW_READ_OFTEN, reinterpret_cast<void**>(&grallocData));
+  graphicBuffer->lock(GRALLOC_USAGE_SW_READ_OFTEN, reinterpret_cast<void**>(&grallocData));
   RefPtr<gfx::DataSourceSurface> grallocTempSurf =
     gfx::Factory::CreateWrappingDataSourceSurface(grallocData,
                                                   graphicBuffer->getStride() * android::bytesPerPixel(graphicBuffer->getPixelFormat()),