diff --git a/.github/actions/install/action.yml b/.github/actions/install/action.yml
index d347f11b..2acb71b8 100644
--- a/.github/actions/install/action.yml
+++ b/.github/actions/install/action.yml
@@ -66,3 +66,7 @@ runs:
 
         mkdir -p v8/out/${{ inputs.os }}/release/obj/zig/
         ln -s ${{ inputs.cache-dir }}/v8/libc_v8.a v8/out/${{ inputs.os }}/release/obj/zig/libc_v8.a
+
+    - name: build html5ever
+      shell: bash
+      run: make install-html5ever
diff --git a/Dockerfile b/Dockerfile
index 24936ffb..76531df7 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -40,6 +40,8 @@ WORKDIR /browser
 RUN git submodule init && \
     git submodule update --recursive
 
+RUN make install-html5ever
+
 # download and install v8
 RUN case $TARGETPLATFORM in \
     "linux/arm64") ARCH="aarch64" ;; \
diff --git a/README.md b/README.md
index a51ba298..f40eab57 100644
--- a/README.md
+++ b/README.md
@@ -215,6 +215,16 @@ To init or update the submodules in the `vendor/` directory:
 make install-submodule
 ```
 
+**html5ever**
+
+[html5ver](https://github.com/servo/html5ever) is high-performance browser-grade HTML5 parser.
+
+```
+make install-html5ever
+```
+
+For dev env, use `make install-html5ever-dev`.
+
 **v8**
 
 First, get the tools necessary for building V8, as well as the V8 source code: