diff --git a/tests/phpunit/tests/admin/includes/misc/wpCheckPhpVersion.php b/tests/phpunit/tests/admin/includes/misc/wpCheckPhpVersion.php
new file mode 100644
index 0000000000000..cfa5e36cea85e
--- /dev/null
+++ b/tests/phpunit/tests/admin/includes/misc/wpCheckPhpVersion.php
@@ -0,0 +1,165 @@
+<?php
+
+/**
+ * @group admin
+ * @group includes
+ * @covers ::wp_check_php_version
+ */
+class Tests_Admin_Includes_Misc_WpCheckPhpVersion extends WP_UnitTestCase {
+
+	/**
+	 * Cleans up transients after each test.
+	 */
+	public function tear_down() {
+		$version = PHP_VERSION;
+		$key     = md5( $version );
+		delete_site_transient( 'php_check_' . $key );
+		parent::tear_down();
+	}
+
+	/**
+	 * @ticket 65203
+	 */
+	public function test_wp_check_php_version_returns_false_on_api_failure() {
+		add_filter( 'pre_http_request', array( $this, 'mock_api_failure' ), 10, 3 );
+
+		$result = wp_check_php_version();
+
+		remove_filter( 'pre_http_request', array( $this, 'mock_api_failure' ) );
+
+		$this->assertFalse( $result, 'wp_check_php_version() should return false on API failure.' );
+	}
+
+	/**
+	 * @ticket 65203
+	 */
+	public function test_wp_check_php_version_successful_response() {
+		add_filter( 'pre_http_request', array( $this, 'mock_api_success' ), 10, 3 );
+
+		$result = wp_check_php_version();
+
+		remove_filter( 'pre_http_request', array( $this, 'mock_api_success' ) );
+
+		$this->assertIsArray( $result, 'wp_check_php_version() should return an array on successful API response.' );
+		$this->assertSame( '8.2', $result['recommended_version'] );
+		$this->assertSame( '7.4', $result['minimum_version'] );
+		$this->assertTrue( $result['is_supported'] );
+		$this->assertTrue( $result['is_secure'] );
+	}
+
+	/**
+	 * @ticket 65203
+	 */
+	public function test_wp_check_php_version_caches_result_in_transient() {
+		add_filter( 'pre_http_request', array( $this, 'mock_api_success' ), 10, 3 );
+
+		wp_check_php_version();
+
+		remove_filter( 'pre_http_request', array( $this, 'mock_api_success' ) );
+
+		$version = PHP_VERSION;
+		$key     = md5( $version );
+		$cached  = get_site_transient( 'php_check_' . $key );
+
+		$this->assertIsArray( $cached, 'Result should be cached in a site transient.' );
+		$this->assertSame( '8.2', $cached['recommended_version'] );
+	}
+
+	/**
+	 * @ticket 65203
+	 */
+	public function test_wp_check_php_version_uses_cached_result() {
+		$version = PHP_VERSION;
+		$key     = md5( $version );
+		$cached  = array(
+			'recommended_version' => '8.3',
+			'minimum_version'     => '7.4',
+			'is_supported'        => true,
+			'is_secure'           => true,
+			'is_acceptable'       => true,
+		);
+		set_site_transient( 'php_check_' . $key, $cached );
+
+		// If it hits the API, it will return the mocked success version (8.2) instead of 8.3.
+		add_filter( 'pre_http_request', array( $this, 'mock_api_success' ), 10, 3 );
+
+		$result = wp_check_php_version();
+
+		remove_filter( 'pre_http_request', array( $this, 'mock_api_success' ) );
+
+		$this->assertSame( '8.3', $result['recommended_version'], 'wp_check_php_version() should use the cached result if available.' );
+	}
+
+	/**
+	 * @ticket 65203
+	 */
+	public function test_wp_is_php_version_acceptable_filter() {
+		add_filter( 'pre_http_request', array( $this, 'mock_api_success' ), 10, 3 );
+		add_filter( 'wp_is_php_version_acceptable', '__return_false' );
+
+		$result = wp_check_php_version();
+
+		remove_filter( 'pre_http_request', array( $this, 'mock_api_success' ) );
+		remove_filter( 'wp_is_php_version_acceptable', '__return_false' );
+
+		if ( version_compare( PHP_VERSION, '8.0', '<' ) ) {
+			$this->markTestSkipped( 'PHP < 8.0 logic overrides the filter result in the tested function.' );
+		}
+
+		$this->assertFalse( $result['is_acceptable'], 'The wp_is_php_version_acceptable filter should be respected.' );
+	}
+
+	/**
+	 * @ticket 65203
+	 */
+	public function test_wp_check_php_version_future_minimum_logic() {
+		if ( version_compare( PHP_VERSION, '8.0', '>=' ) ) {
+			$this->markTestSkipped( 'This test is only relevant for PHP < 8.0.' );
+		}
+
+		add_filter( 'pre_http_request', array( $this, 'mock_api_success' ), 10, 3 );
+
+		$result = wp_check_php_version();
+
+		remove_filter( 'pre_http_request', array( $this, 'mock_api_success' ) );
+
+		$this->assertTrue( $result['is_lower_than_future_minimum'], 'is_lower_than_future_minimum should be true for PHP < 8.0.' );
+		$this->assertFalse( $result['is_acceptable'], 'is_acceptable should be false for PHP < 8.0 regardless of API response.' );
+	}
+
+	/**
+	 * Mock HTTP request for API success.
+	 *
+	 * @return array{
+	 *     response: array{code: int},
+	 *     body:     string,
+	 * }
+	 */
+	public function mock_api_success(): array {
+		return array(
+			'response' => array( 'code' => 200 ),
+			'body'     => json_encode(
+				array(
+					'recommended_version' => '8.2',
+					'minimum_version'     => '7.4',
+					'is_supported'        => true,
+					'is_secure'           => true,
+					'is_acceptable'       => true,
+				)
+			),
+		);
+	}
+
+	/**
+	 * Mock HTTP request for API failure.
+	 *
+	 * @return array{
+	 *     response: array{code: int},
+	 * }
+	 */
+	public function mock_api_failure(): array {
+		return array(
+			'response' => array( 'code' => 500 ),
+		);
+	}
+}