diff --git a/taskcluster/ci/webrender/kind.yml b/taskcluster/ci/webrender/kind.yml
index 5878c2b30c63..3e3c6ca73cca 100644
--- a/taskcluster/ci/webrender/kind.yml
+++ b/taskcluster/ci/webrender/kind.yml
@@ -91,6 +91,68 @@ jobs:
             files-changed:
                 - 'gfx/wr/**'
 
+    wrench-macos-build:
+        description: Cross compilation of wrench for macOS on Linux
+        worker-type: aws-provisioner-v1/gecko-{level}-b-linux
+        worker:
+            docker-image: {in-tree: webrender}
+            env:
+                TOOLTOOL_MANIFEST: "/builds/worker/checkouts/gecko/browser/config/tooltool-manifests/macosx64/cross-releng.manifest"
+            chain-of-trust: true
+            artifacts:
+                - type: file
+                  name: public/build/wrench-macos.tar.bz2
+                  path: /builds/worker/artifacts/wrench-macos.tar.bz2
+                - type: file
+                  name: public/build/wrench-macos-headless.tar.bz2
+                  path: /builds/worker/artifacts/wrench-macos-headless.tar.bz2
+        toolchains:
+            - linux64-rust-macos
+            - linux64-cctools-port
+            - linux64-clang
+            - linux64-llvm-dsymutil
+            - wrench-deps
+        run:
+            using: run-task
+            tooltool-downloads: internal
+            command: '$HOME/checkouts/gecko/taskcluster/scripts/misc/wrench-macos-build.sh'
+        treeherder:
+            platform: macosx64-qr/opt
+            symbol: WR(B)
+        when:
+            files-changed:
+                - 'gfx/wr/**'
+                - 'taskcluster/scripts/misc/tooltool-download.sh'
+                - 'taskcluster/scripts/misc/wr-macos-cross-build-setup.sh'
+                - 'taskcluster/scripts/misc/wrench-macos-build.sh'
+
+    macos-release:
+        description: Runs release-mode WebRender CI tests on a macOS worker
+        worker-type: releng-hardware/gecko-t-osx-1010
+        worker:
+            max-run-time: 3600
+            env:
+                MOZ_FETCHES_DIR: 'checkouts/gecko/gfx/wr'
+        dependencies:
+            webrender-wrench-macos-build: webrender-wrench-macos-build
+        fetches:
+            webrender-wrench-macos-build:
+                - 'wrench-macos.tar.bz2'
+                - 'wrench-macos-headless.tar.bz2'
+        run:
+            using: run-task
+            command: >-
+                cd $GECKO_PATH/gfx/wr &&
+                export WRENCH_HEADLESS_TARGET=$PWD/wrench-macos-headless/ &&
+                export WRENCH_BINARY=$PWD/wrench-macos/bin/wrench &&
+                ci-scripts/macos-release-tests.sh
+        treeherder:
+            platform: macosx64-qr/opt
+            symbol: WR(wrench)
+        when:
+            files-changed:
+                - 'gfx/wr/**'
+
     windows:
         description: Runs WebRender CI tests on a Windows worker
         worker-type: aws-provisioner-v1/gecko-t-win10-64
diff --git a/taskcluster/scripts/misc/wr-macos-cross-build-setup.sh b/taskcluster/scripts/misc/wr-macos-cross-build-setup.sh
new file mode 100644
index 000000000000..bf39d4492f81
--- /dev/null
+++ b/taskcluster/scripts/misc/wr-macos-cross-build-setup.sh
@@ -0,0 +1,81 @@
+#!/bin/bash
+set -x -e -v
+
+export WORKSPACE="/builds/worker/workspace"
+export TOOLS_DIR="${WORKSPACE}/build/src"
+export TARGET_TRIPLE="x86_64-apple-darwin"
+
+mkdir -p "${TOOLS_DIR}"
+
+# The tooltool-download script assumes that the gecko checkout is in
+# ${WORKSPACE}/build/src and that it can run `./mach` there. This is not
+# true when using run-task (which is what this script runs with) so we
+# symlink mach to satisfy tooltool-download's assumptions.
+ln -s "${GECKO_PATH}/mach" "${TOOLS_DIR}"
+source "${GECKO_PATH}/taskcluster/scripts/misc/tooltool-download.sh"
+
+MACOS_SYSROOT="${TOOLS_DIR}/MacOSX10.11.sdk"
+CLANGDIR="${TOOLS_DIR}/clang"
+
+# Deploy the wrench dependencies
+mv ${TOOLS_DIR}/wrench-deps/{vendor,.cargo} "${GECKO_PATH}/gfx/wr/"
+
+# Building wrench with the `headless` feature also builds the osmesa-src crate,
+# which includes building C++ code. We have to do a bunch of shenanigans
+# to make this cross-compile properly.
+
+pushd "${TOOLS_DIR}/cctools/bin"
+# Link all the tools from x86_64-darwin11-* to x86_64-apple-darwin-* because
+# x86_64-apple-darwin is the Official Rust Triple (TM) and so that's the prefix
+# we run configure with, and the toolchain configure/make will look for.
+# We can't just rename the files because e.g. the ar tool invokes the ranlib
+# tool with the old prefix hard-coded. So we symlink instead.
+for TOOL in x86_64-darwin11-*; do
+    ln -s "${TOOL}" "${TOOL/x86_64-darwin11/${TARGET_TRIPLE}}"
+done
+
+# Add a pkg-config cross-compile wrapper. Without this, the configure script
+# will use pkg-config from the host, which will find host libraries that are
+# not what we want. This script stolen from
+# https://autotools.io/pkgconfig/cross-compiling.html
+cat > ${TARGET_TRIPLE}-pkg-config <<END_PKGCONFIG_WRAPPER
+#!/bin/sh
+export PKG_CONFIG_DIR=
+export PKG_CONFIG_LIBDIR=${MACOS_SYSROOT}/usr/lib/pkgconfig:${MACOS_SYSROOT}/usr/share/pkgconfig
+export PKG_CONFIG_SYSROOT_DIR=${MACOS_SYSROOT}
+exec pkg-config "$@"
+END_PKGCONFIG_WRAPPER
+chmod +x "${TARGET_TRIPLE}-pkg-config"
+popd
+
+# The PATH intentionally excludes clang/bin because osmesa will try to
+# build llvmpipe if it finds a llvm-config. And that will fail because
+# we don't have a target libLLVM library to link with. We don't need
+# llvmpipe anyway since we only use the softpipe driver. If for whatever
+# reason we need to add clang/bin to the path here, we should be able to
+# instead set LLVM_CONFIG=no to disable llvmpipe, but that might impact
+# other parts of the build.
+export PATH="${TOOLS_DIR}/rustc/bin:${TOOLS_DIR}/cctools/bin:${TOOLS_DIR}/llvm-dsymutil/bin:${PATH}"
+
+# The x86_64-darwin11-ld linker from cctools requires libraries provided
+# by clang, so we need to set LD_LIBRARY_PATH for that to work.
+export LD_LIBRARY_PATH="${CLANGDIR}/lib:${LD_LIBRARY_PATH}"
+
+# Tell the configure script where to find zlib, because otherwise it tries
+# to use pkg-config to find it, which fails (no .pc file in the macos SDK).
+export ZLIB_CFLAGS="-I${MACOS_SYSROOT}/usr/include"
+export ZLIB_LIBS="-L${MACOS_SYSROOT}/usr/lib -lz"
+
+# Set up compiler and flags for cross-compile
+LDPATH="${TOOLS_DIR}/cctools/bin/${TARGET_TRIPLE}-ld"
+export CC="${CLANGDIR}/bin/clang"
+export CFLAGS="-fuse-ld=${LDPATH} -target ${TARGET_TRIPLE} -mmacosx-version-min=10.7 --rtlib=compiler-rt --sysroot ${MACOS_SYSROOT}"
+export CXX="${CLANGDIR}/bin/clang++"
+export CXXFLAGS="-fuse-ld=${LDPATH} -target ${TARGET_TRIPLE} -mmacosx-version-min=10.7 --rtlib=compiler-rt --sysroot ${MACOS_SYSROOT} -stdlib=libc++"
+
+# See documentation in cargo-linker for why we need this. TL;DR is that passing
+# the right arguments to the linker when invoked by cargo is nigh impossible
+# without this.
+export MOZ_CARGO_WRAP_LD="${CC}"
+export MOZ_CARGO_WRAP_LDFLAGS="${CFLAGS}"
+export CARGO_TARGET_X86_64_APPLE_DARWIN_LINKER="${GECKO_PATH}/build/cargo-linker"
diff --git a/taskcluster/scripts/misc/wrench-macos-build.sh b/taskcluster/scripts/misc/wrench-macos-build.sh
new file mode 100755
index 000000000000..4c885c1e9f40
--- /dev/null
+++ b/taskcluster/scripts/misc/wrench-macos-build.sh
@@ -0,0 +1,46 @@
+#!/bin/bash
+set -x -e -v
+
+source ${GECKO_PATH}/taskcluster/scripts/misc/wr-macos-cross-build-setup.sh
+
+# The osmesa-src build which we do as part of the headless build below
+# doesn't seem to always use CFLAGS/CXXFLAGS where expected. Instead we
+# just squash those flags into CC/CXX and everything works out.
+export CC="${CC} ${CFLAGS}"
+export CFLAGS=
+export CXX="${CXX} ${CXXFLAGS}"
+export CXXFLAGS=
+
+export UPLOAD_DIR="${HOME}/artifacts"
+mkdir -p "${UPLOAD_DIR}"
+
+# Do a cross-build without the `headless` feature
+pushd "${GECKO_PATH}/gfx/wr/wrench"
+cargo build --release -vv --frozen --target=${TARGET_TRIPLE}
+# Package up the resulting wrench binary
+cd "../target/${TARGET_TRIPLE}"
+mkdir -p wrench-macos/bin
+mv release/wrench wrench-macos/bin/
+tar cjf wrench-macos.tar.bz2 wrench-macos
+mv wrench-macos.tar.bz2 "${UPLOAD_DIR}"
+# Clean the build
+cd "${GECKO_PATH}/gfx/wr"
+rm -rf target
+popd
+
+# Do a cross-build with the `headless` feature
+pushd "${GECKO_PATH}/gfx/wr/wrench"
+cargo build --release -vv --frozen --target=${TARGET_TRIPLE} --features headless
+# Package up the wrench binary and some libraries that we will need
+cd "../target/${TARGET_TRIPLE}"
+mkdir wrench-macos-headless
+mv release wrench-macos-headless/
+tar cjf wrench-macos-headless.tar.bz2 \
+    wrench-macos-headless/release/wrench \
+    wrench-macos-headless/release/build/osmesa-src*/out/src/gallium/targets/osmesa/.libs \
+    wrench-macos-headless/release/build/osmesa-src*/out/src/mapi/shared-glapi/.libs
+mv wrench-macos-headless.tar.bz2 "${UPLOAD_DIR}"
+# Clean the build
+cd "${GECKO_PATH}/gfx/wr"
+rm -rf target
+popd