diff --git a/.tugboat/steps/3-build.sh b/.tugboat/steps/3-build.sh
index fed78af8..58ea5894 100755
--- a/.tugboat/steps/3-build.sh
+++ b/.tugboat/steps/3-build.sh
@@ -6,5 +6,7 @@
 set -eux
 echo "Building..."
 
+composer install
+
 ./vendor/bin/task build
 ./vendor/bin/task update
diff --git a/scaffold/tugboat/steps/3-build.sh.twig b/scaffold/tugboat/steps/3-build.sh.twig
index ad88cb45..4d8dcbc9 100644
--- a/scaffold/tugboat/steps/3-build.sh.twig
+++ b/scaffold/tugboat/steps/3-build.sh.twig
@@ -6,5 +6,7 @@
 set -eux
 echo "Building..."
 
+composer install
+
 ./vendor/bin/task {{ build_command }}
 ./vendor/bin/task {{ update_command }}