diff --git a/.env b/.env
index 30e42fbb3404f..7d7a2c16462ef 100644
--- a/.env
+++ b/.env
@@ -6,7 +6,6 @@
 #
 # Below, the following substitutions can be made:
 # - '{version}': any major.minor PHP version from 5.2 onwards.
-# - '{phpunit_version}': any major PHPUnit version starting with 4.
 ##
 
 # The site will be available at http://localhost:LOCAL_PORT
@@ -18,27 +17,6 @@ LOCAL_DIR=src
 # The PHP version to use. Valid options are 'latest', and '{version}-fpm'.
 LOCAL_PHP=8.0-fpm
 
-##
-# The PHPUnit version to use when running tests.
-#
-# Support for new PHPUnit versions is not backported to past versions, so some old WordPress branches require an older
-# version to run tests.
-#
-# Valid versions are:
-# - 'latest' for the highest version of PHPUnit supported on the highest version of PHP supported.
-# - '{version}-fpm' for the highest version of PHPUnit supported on the specified version of PHP.
-# - '{phpunit_version}-php-{version}-fpm' for a specific version of PHPUnit on the specified version of PHP. This format
-# is only available for PHP versions 5.6 and higher.
-#
-# For the full list of available options, see https://hub.docker.com/r/wordpressdevelop/phpunit/tags.
-#
-# For full documentation on PHPUnit compatibility and WordPress versions, see
-# https://make.wordpress.org/core/handbook/references/phpunit-compatibility-and-wordpress-versions/.
-#
-# This defaults to the value assigned to the value of LOCAL_PHP.
-##
-LOCAL_PHPUNIT=${LOCAL_PHP}
-
 # Whether or not to enable XDebug.
 LOCAL_PHP_XDEBUG=false
 
diff --git a/package.json b/package.json
index 889f218923f01..92f91ff17dc25 100644
--- a/package.json
+++ b/package.json
@@ -170,8 +170,7 @@
 		"env:cli": "node ./tools/local-env/scripts/docker.js run cli",
 		"env:logs": "node ./tools/local-env/scripts/docker.js logs",
 		"env:pull": "node ./tools/local-env/scripts/docker.js pull",
-		"test:php": "node ./tools/local-env/scripts/docker.js run --rm phpunit phpunit",
-		"test:php-composer": "node ./tools/local-env/scripts/docker.js run --rm phpunit php ./vendor/bin/phpunit",
+		"test:php": "node ./tools/local-env/scripts/docker.js run -T php composer update -W && node ./tools/local-env/scripts/docker.js run php ./vendor/bin/phpunit",
 		"test:e2e": "node ./tests/e2e/run-tests.js",
 		"wp-packages-update": "wp-scripts packages-update"
 	}