diff --git a/CHANGELOG.md b/CHANGELOG.md
index 17e1458..1f36a5b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## UNRELEASED
+- add support for project config files using .yaml extension
+
 ## 0.14.0
 ### Misc
 - Add `--suppress-tmux-version-warning` flag to prevent tmux version warning (#583)
diff --git a/lib/tmuxinator/config.rb b/lib/tmuxinator/config.rb
index 522c18a..d25ef30 100644
--- a/lib/tmuxinator/config.rb
+++ b/lib/tmuxinator/config.rb
@@ -181,8 +181,8 @@ module Tmuxinator
       # recursively searching 'directory'
       def project_in(directory, name)
         return nil if String(directory).empty?
-        projects = Dir.glob("#{directory}/**/*.yml").sort
-        projects.detect { |project| File.basename(project, ".yml") == name }
+        projects = Dir.glob("#{directory}/**/*.{yml,yaml}").sort
+        projects.detect { |project| File.basename(project, ".*") == name }
       end
     end
   end
diff --git a/spec/fixtures/yaml.yaml b/spec/fixtures/yaml.yaml
new file mode 100644
index 0000000..0889d48
--- /dev/null
+++ b/spec/fixtures/yaml.yaml
@@ -0,0 +1,40 @@
+# ~/.tmuxinator/sample.yml
+# you can make as many tabs as you wish...
+
+name: sample
+root: ~/test
+socket_name: foo # Remove to use default socket
+pre_window: rbenv shell 2.0.0-p247 # Runs in each tab and pane
+tmux_options: -f ~/.tmux.mac.conf # Pass arguments to tmux
+tmux_detached: false
+windows:
+  - editor:
+      pre:
+        - echo "I get run in each pane, before each pane command!"
+        -
+      layout: main-vertical
+      panes:
+        - vim
+        - #empty, will just run plain bash
+        - top
+        - pane_with_multiple_commands:
+            - ssh server
+            - echo "Hello"
+  - shell:
+    - git pull
+    - git merge
+  - guard:
+      layout: tiled
+      pre:
+        - echo "I get run in each pane."
+        - echo "Before each pane command!"
+      panes:
+        -
+        - #empty, will just run plain bash
+        -
+  - database: bundle exec rails db
+  - server: bundle exec rails s
+  - logs: tail -f log/development.log
+  - console: bundle exec rails c
+  - capistrano:
+  - server: ssh user@example.com
diff --git a/spec/lib/tmuxinator/config_spec.rb b/spec/lib/tmuxinator/config_spec.rb
index 7d2f811..abdb2df 100644
--- a/spec/lib/tmuxinator/config_spec.rb
+++ b/spec/lib/tmuxinator/config_spec.rb
@@ -246,6 +246,7 @@ describe Tmuxinator::Config do
     let(:directory) { Tmuxinator::Config.directory }
     let(:base) { "#{directory}/sample.yml" }
     let(:first_dup) { "#{home_config_dir}/dup/local-dup.yml" }
+    let(:yaml) { "#{directory}/yaml.yaml" }
 
     before do
       allow(Tmuxinator::Config).to receive_messages(xdg: fixtures_dir)
@@ -258,6 +259,12 @@ describe Tmuxinator::Config do
       end
     end
 
+    context "with project yaml" do
+      it "gets the project as path to the yaml file" do
+        expect(Tmuxinator::Config.global_project("yaml")).to eq yaml
+      end
+    end
+
     context "without project yml" do
       it "gets the project as path to the yml file" do
         expect(Tmuxinator::Config.global_project("new-project")).to be_nil