diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 900dcf3..53dafce 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,13 +18,13 @@ jobs:
           mkdir build/
           mv hello.php build/
 
-      - name: Run plugin check
+      - name: Run plugin check (default)
         uses: ./
         continue-on-error: true # Since we expect it to always fail for the test plugin.
         with:
           build-dir: 'build'
 
-      - name: Run plugin check
+      - name: Run plugin check (exclude checks)
         uses: ./
         continue-on-error: true # Since we expect it to always fail for the test plugin.
         with:
@@ -33,3 +33,10 @@ jobs:
             late_escaping
             plugin_readme
           include-experimental: true
+
+      - name: Run plugin check (trunk)
+        uses: ./
+        continue-on-error: true # Since we expect it to always fail for the test plugin.
+        with:
+          build-dir: 'build'
+          wp-version: 'trunk'
diff --git a/README.md b/README.md
index a01e632..a12fcf8 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,11 @@ See [action.yml](action.yml)
     #
     # Default: true
     include-experimental: ''
+
+    # WordPress version to use. Supports "latest" or "trunk".
+    #
+    # Default: latest
+    wp-version: ''
 ```
 
 ### Basic
diff --git a/action.yml b/action.yml
index 0990b15..b0d75bb 100644
--- a/action.yml
+++ b/action.yml
@@ -41,6 +41,10 @@ inputs:
     description: 'Include experimental checks'
     required: false
     default: 'false'
+  wp-version:
+    description: 'WordPress version to use'
+    required: false
+    default: 'latest'
 runs:
   using: "composite"
   steps:
@@ -84,11 +88,13 @@ runs:
       run: |
         touch .wp-env.json
         > .wp-env.json
-        echo "{ \"core\": null, \"port\": 8880, \"testsPort\": 8881, \"plugins\": [ \"$PLUGIN_DIR\", \"plugin-check\" ] }" >> .wp-env.json
+        echo "{ \"core\": $WP_VERSION, \"port\": 8880, \"testsPort\": 8881, \"plugins\": [ \"$PLUGIN_DIR\", \"https://downloads.wordpress.org/plugin/plugin-check.1.0.0.zip\" ] }" >> .wp-env.json
 
-        npm -g i @wordpress/env
+        npm -g --no-fund i @wordpress/env
         wp-env start --update
       shell: bash
+      env:
+        WP_VERSION: ${{ inputs.wp-version == 'trunk' && '"WordPress/WordPress#master"' || 'null' }}
 
     - name: Run Plugin Check
       run: |