diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 2de81e5a20..014a9aca0f 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -74,13 +74,15 @@ jobs:
         - aarch64-unknown-linux-gnu
         - riscv64gc-unknown-linux-gnu
         - powerpc64le-unknown-linux-gnu
-        - mips-unknown-linux-gnu
-        - mips64-unknown-linux-gnuabi64
-        - mips64el-unknown-linux-gnuabi64
+        # MIPS targets disabled since they are dropped to tier 3.
+        # See https://github.com/rust-lang/compiler-team/issues/648
+        #- mips-unknown-linux-gnu
+        #- mips64-unknown-linux-gnuabi64
+        #- mips64el-unknown-linux-gnuabi64
+        #- mipsel-unknown-linux-musl
         - s390x-unknown-linux-gnu
         - wasm32-wasi
         - i586-unknown-linux-gnu
-        - mipsel-unknown-linux-musl
         - nvptx64-nvidia-cuda
         - thumbv6m-none-eabi
         - thumbv7m-none-eabi
@@ -114,15 +116,20 @@ jobs:
           os: ubuntu-latest
         - target: armv7-unknown-linux-gnueabihf
           os: ubuntu-latest
-        - target: mips-unknown-linux-gnu
-          os: ubuntu-latest
-          norun: true
-        - target: mips64-unknown-linux-gnuabi64
-          os: ubuntu-latest
-          norun: true
-        - target: mips64el-unknown-linux-gnuabi64
-          os: ubuntu-latest
-          norun: true
+        # MIPS targets disabled since they are dropped to tier 3.
+        # See https://github.com/rust-lang/compiler-team/issues/648
+        #- target: mips-unknown-linux-gnu
+        #  os: ubuntu-latest
+        #  norun: true
+        #- target: mips64-unknown-linux-gnuabi64
+        #  os: ubuntu-latest
+        #  norun: true
+        #- target: mips64el-unknown-linux-gnuabi64
+        #  os: ubuntu-latest
+        #  norun: true
+        #- target: mipsel-unknown-linux-musl
+        #  os: ubuntu-latest
+        #  norun: 1
         - target: powerpc64le-unknown-linux-gnu
           os: ubuntu-latest
           disable_assert_instr: true
@@ -143,9 +150,6 @@ jobs:
           os: windows-latest
         - target: i586-unknown-linux-gnu
           os: ubuntu-latest
-        - target: mipsel-unknown-linux-musl
-          os: ubuntu-latest
-          norun: 1
         - target: nvptx64-nvidia-cuda
           os: ubuntu-latest
         - target: thumbv6m-none-eabi
diff --git a/ci/dox.sh b/ci/dox.sh
index 3e507b4563..cc207cb353 100755
--- a/ci/dox.sh
+++ b/ci/dox.sh
@@ -45,6 +45,8 @@ dox arm armv7-unknown-linux-gnueabihf
 dox aarch64 aarch64-unknown-linux-gnu
 dox powerpc powerpc-unknown-linux-gnu
 dox powerpc64le powerpc64le-unknown-linux-gnu
-dox mips mips-unknown-linux-gnu
-dox mips64 mips64-unknown-linux-gnuabi64
+# MIPS targets disabled since they are dropped to tier 3.
+# See https://github.com/rust-lang/compiler-team/issues/648
+#dox mips mips-unknown-linux-gnu
+#dox mips64 mips64-unknown-linux-gnuabi64
 dox wasm32 wasm32-unknown-unknown