diff --git a/.github/workflows/master.yml b/.github/workflows/master.yml
index 7766fb35..39a0338a 100644
--- a/.github/workflows/master.yml
+++ b/.github/workflows/master.yml
@@ -4,13 +4,12 @@ on:
   push:
     branches:
       - master
-
   pull_request:
 
 jobs:
-  build:
+  postgres:
     runs-on: ubuntu-latest
-    name: Ruby ${{ matrix.ruby }}
+    name: Ruby ${{ matrix.ruby }} with PostgreSQL
     strategy:
       matrix:
         ruby:
@@ -19,10 +18,13 @@ jobs:
       postgres:
         image: postgres:latest
         env:
+          DATABASE_ADAPTER: postgresql
+          DATABASE_PORT: 5432
           POSTGRES_USER: outboxer_developer
           POSTGRES_PASSWORD: outboxer_password
           POSTGRES_DB: outboxer_test
-        ports: ['5432:5432']
+        ports:
+          - 5432:5432
         options: --health-cmd pg_isready --health-interval 10s --health-timeout 5s --health-retries 5
     steps:
     - uses: actions/checkout@v3
@@ -38,5 +40,57 @@ jobs:
         psql -h localhost -U outboxer_developer -d outboxer_test -c 'SELECT version();'
     - name: Run Database Migrations
       run: RAILS_ENV=test bin/rake outboxer:db:migrate
-    - name: Run the default task
+    - name: Run Tests
       run: RAILS_ENV=test bin/rspec spec
+
+  mysql:
+    runs-on: ubuntu-latest
+    name: Ruby ${{ matrix.ruby }} with MySQL
+    strategy:
+      matrix:
+        ruby:
+          - '3.3.0'
+    services:
+      mysql:
+        image: mysql:latest
+        env:
+          DATABASE_ADAPTER: mysql2
+          DATABASE_PORT: 3306
+          MYSQL_ROOT_PASSWORD: outboxer_password
+          MYSQL_DATABASE: outboxer_test
+          MYSQL_USER: outboxer_developer
+          MYSQL_PASSWORD: outboxer_password
+        ports:
+          - 3306:3306
+        options: >-
+          --health-cmd="mysqladmin ping --silent"
+          --health-interval=10s
+          --health-timeout=5s
+          --health-retries=5
+    steps:
+    - uses: actions/checkout@v3
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+        bundler-cache: true
+    - name: Check MySQL
+      run: |
+        sudo apt-get -qq install -y mysql-client
+        export MYSQL_PWD=outboxer_password
+        mysql -h 127.0.0.1 -P 3306 -u outboxer_developer -poutboxer_password outboxer_test -e 'SELECT VERSION();'
+    - name: Run Database Migrations
+      env:
+        RAILS_ENV: test
+        DATABASE_ADAPTER: mysql2
+        DATABASE_HOST: 127.0.0.1
+        DATABASE_PORT: 3306
+      run: |
+        bin/rake outboxer:db:migrate
+    - name: Run Tests
+      env:
+        RAILS_ENV: test
+        DATABASE_ADAPTER: mysql2
+        DATABASE_PORT: 3306
+        DATABASE_HOST: 127.0.0.1
+      run: bin/rspec spec
diff --git a/Gemfile b/Gemfile
index 052f995c..d1168d1b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,6 +10,7 @@ gem "rubocop", "~> 1.55"
 gem "yard", "~> 0.9.34"
 
 gem "pg", "~> 1.5"
+gem 'mysql2', '~> 0.5.6'
 gem "activerecord", "~> 7.1", ">= 7.1.2"
 
 gem "sidekiq", "~> 7.2"
diff --git a/Gemfile.lock b/Gemfile.lock
index f9a03fc4..0ea36c40 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -75,6 +75,7 @@ GEM
     method_source (1.0.0)
     minitest (5.20.0)
     mutex_m (0.2.0)
+    mysql2 (0.5.6)
     nokogiri (1.16.2-arm64-darwin)
       racc (~> 1.4)
     nokogiri (1.16.2-x86_64-darwin)
@@ -85,7 +86,7 @@ GEM
     parser (3.2.2.3)
       ast (~> 2.4.1)
       racc
-    pg (1.5.3)
+    pg (1.5.6)
     pry (0.14.2)
       coderay (~> 1.1)
       method_source (~> 1.0)
@@ -162,6 +163,7 @@ DEPENDENCIES
   database_cleaner (~> 2.0, >= 2.0.2)
   factory_bot (~> 6.4, >= 6.4.6)
   foreman (~> 0.87.2)
+  mysql2 (~> 0.5.6)
   outboxer!
   pg (~> 1.5)
   pry-byebug (~> 3.10)
diff --git a/config/database.yml b/config/database.yml
index 345bd188..6a8c6a97 100644
--- a/config/database.yml
+++ b/config/database.yml
@@ -1,19 +1,19 @@
 development:
-  adapter: postgresql
-  encoding: unicode
-  host: localhost
-  port: 5432
+  adapter: <%= ENV.fetch('DATABASE_ADAPTER') { 'postgresql' } %>
+  encoding: utf8
+  host: <%= ENV.fetch('DATABASE_HOST') { 'localhost' } %>
+  port: <%= ENV.fetch('DATABASE_PORT') { 5432 } %>
   username: outboxer_developer
   password: outboxer_password
   database: outboxer_development
-  pool: <%= ENV.fetch('RAILS_MAX_THREADS') { 26 } %>
+  pool: <%= ENV.fetch('DATABASE_POOL') { 5 } %>
 
 test:
-  adapter: postgresql
-  encoding: unicode
-  host: localhost
-  port: 5432
+  adapter: <%= ENV.fetch('DATABASE_ADAPTER') { 'postgresql' } %>
+  encoding: utf8
+  host: <%= ENV.fetch('DATABASE_HOST') { 'localhost' } %>
+  port: <%= ENV.fetch('DATABASE_PORT') { 5432 } %>
   username: outboxer_developer
   password: outboxer_password
   database: outboxer_test
-  pool: <%= ENV.fetch('RAILS_MAX_THREADS') { 26 } %>
+  pool: <%= ENV.fetch('DATABASE_POOL') { 5 } %>
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 57ff2444..f697f712 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -31,7 +31,9 @@
       DatabaseCleaner.clean
 
       ActiveRecord::Base.connection.tables.each do |table|
-        ActiveRecord::Base.connection.reset_pk_sequence!(table)
+        if ActiveRecord::Base.connection.adapter_name == 'PostgreSQL'
+          ActiveRecord::Base.connection.reset_pk_sequence!(table)
+        end
       end
     rescue ActiveRecord::DatabaseConnectionError,
         ActiveRecord::ConnectionNotEstablished,