diff --git a/src/Symfony/Component/Dotenv/Command/DebugCommand.php b/src/Symfony/Component/Dotenv/Command/DebugCommand.php
index 8ceb1fd484845..bad818fdc29e8 100644
--- a/src/Symfony/Component/Dotenv/Command/DebugCommand.php
+++ b/src/Symfony/Component/Dotenv/Command/DebugCommand.php
@@ -49,17 +49,20 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             return 1;
         }
 
-        $envFiles = $this->getEnvFiles();
+        $dotenvFile = $this->getDotenvFile();
+        $envFiles = $this->getEnvFiles($dotenvFile);
         $availableFiles = array_filter($envFiles, function (string $file) {
             return is_file($this->getFilePath($file));
         });
 
-        if (\in_array('.env.local.php', $availableFiles, true)) {
-            $io->warning('Due to existing dump file (.env.local.php) all other dotenv files are skipped.');
+        $localDotenvFile = sprintf('%s.local.php', $dotenvFile);
+        if (\in_array($localDotenvFile, $availableFiles, true)) {
+            $io->warning(sprintf('Due to existing dump file (%s) all other dotenv files are skipped.', $localDotenvFile));
         }
 
-        if (is_file($this->getFilePath('.env')) && is_file($this->getFilePath('.env.dist'))) {
-            $io->warning('The file .env.dist gets skipped due to the existence of .env.');
+        $distDotenvFile = sprintf('%s.dist', $dotenvFile);
+        if (is_file($this->getFilePath($dotenvFile)) && is_file($this->getFilePath($distDotenvFile))) {
+            $io->warning(sprintf('The file %s gets skipped due to the existence of %s.', $distDotenvFile, $dotenvFile));
         }
 
         $io->section('Scanned Files (in descending priority)');
@@ -71,7 +74,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 
         $io->section('Variables');
         $io->table(
-            array_merge(['Variable', 'Value'], $availableFiles),
+            array_merge(['Variable', 'Value'], array_map('basename', $availableFiles)),
             $this->getVariables($availableFiles)
         );
 
@@ -104,22 +107,22 @@ private function getVariables(array $envFiles): array
         return $output;
     }
 
-    private function getEnvFiles(): array
+    private function getEnvFiles(string $dotenvFile): array
     {
         $files = [
-            '.env.local.php',
-            sprintf('.env.%s.local', $this->kernelEnvironment),
-            sprintf('.env.%s', $this->kernelEnvironment),
+            sprintf('%s.local.php', $dotenvFile),
+            sprintf('%s.%s.local', $dotenvFile, $this->kernelEnvironment),
+            sprintf('%s.%s', $dotenvFile, $this->kernelEnvironment),
         ];
 
         if ('test' !== $this->kernelEnvironment) {
-            $files[] = '.env.local';
+            $files[] = sprintf('%s.local', $dotenvFile);
         }
 
-        if (!is_file($this->getFilePath('.env')) && is_file($this->getFilePath('.env.dist'))) {
-            $files[] = '.env.dist';
+        if (!is_file($this->getFilePath($dotenvFile)) && is_file($this->getFilePath($distDotenvFile = sprintf('%s.dist', $dotenvFile)))) {
+            $files[] = $distDotenvFile;
         } else {
-            $files[] = '.env';
+            $files[] = $dotenvFile;
         }
 
         return $files;
@@ -140,4 +143,18 @@ private function loadValues(string $file): array
 
         return (new Dotenv())->parse(file_get_contents($filePath));
     }
+
+    private function getDotenvFile(): string
+    {
+        $projectDir = is_file($projectDir = $this->projectDirectory) ? basename($projectDir) : $projectDir;
+
+        $composerFile = $projectDir.'/composer.json';
+        if (is_file($composerFile)) {
+            $composerContent = json_decode(file_get_contents($composerFile), true);
+
+            return $composerContent['extra']['runtime']['dotenv_path'] ?? '.env';
+        }
+
+        return '.env';
+    }
 }
diff --git a/src/Symfony/Component/Dotenv/Tests/Command/DebugCommandTest.php b/src/Symfony/Component/Dotenv/Tests/Command/DebugCommandTest.php
index b3b089e4559c9..79bc5f6a5e88b 100644
--- a/src/Symfony/Component/Dotenv/Tests/Command/DebugCommandTest.php
+++ b/src/Symfony/Component/Dotenv/Tests/Command/DebugCommandTest.php
@@ -122,6 +122,28 @@ public function testScenario2InProdEnv()
         $this->assertStringContainsString('TEST       1234    1234             1234        0000', $output);
     }
 
+    public function testScenario4InProdEnv()
+    {
+        $output = $this->executeCommand(__DIR__.'/Fixtures/Scenario4', 'prod');
+
+        // Scanned Files
+        $this->assertStringContainsString('✓ sub/path/custom.env.local.php', $output);
+        $this->assertStringContainsString('⨯ sub/path/custom.env.prod.local', $output);
+        $this->assertStringContainsString('⨯ sub/path/custom.env.prod', $output);
+        $this->assertStringContainsString('✓ sub/path/custom.env.local', $output);
+        $this->assertStringContainsString('⨯ sub/path/custom.env'.\PHP_EOL, $output);
+
+        // Skipped Files
+        $this->assertStringNotContainsString('custom.env.dist', $output);
+        $this->assertStringNotContainsString('custom.env.dev', $output);
+        $this->assertStringNotContainsString('custom.env.test', $output);
+
+        // Variables
+        $this->assertStringContainsString('Variable   Value   custom.env.local.php   custom.env.local', $output);
+        $this->assertStringContainsString('FOO        BaR     BaR                    n/a', $output);
+        $this->assertStringContainsString('TEST       1234    1234                   1111', $output);
+    }
+
     public function testWarningOnEnvAndEnvDistFile()
     {
         $output = $this->executeCommand(__DIR__.'/Fixtures/Scenario3', 'dev');
diff --git a/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/.env.dist b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/.env.dist
new file mode 100644
index 0000000000000..96c193cbcb47d
--- /dev/null
+++ b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/.env.dist
@@ -0,0 +1 @@
+TEST=0000
diff --git a/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/.env.prod b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/.env.prod
new file mode 100644
index 0000000000000..b3116d1f1d898
--- /dev/null
+++ b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/.env.prod
@@ -0,0 +1,2 @@
+FOO=BaR
+TEST=1234
diff --git a/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/composer.json b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/composer.json
new file mode 100644
index 0000000000000..3c7ca9f0c8127
--- /dev/null
+++ b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/composer.json
@@ -0,0 +1,7 @@
+{
+    "extra": {
+        "runtime": {
+            "dotenv_path": "sub/path/custom.env"
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/sub/path/custom.env.local b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/sub/path/custom.env.local
new file mode 100644
index 0000000000000..5770c3418bdfe
--- /dev/null
+++ b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/sub/path/custom.env.local
@@ -0,0 +1 @@
+TEST=1111
diff --git a/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/sub/path/custom.env.local.php b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/sub/path/custom.env.local.php
new file mode 100644
index 0000000000000..07744b5876e66
--- /dev/null
+++ b/src/Symfony/Component/Dotenv/Tests/Command/Fixtures/Scenario4/sub/path/custom.env.local.php
@@ -0,0 +1,5 @@
+<?php
+return [
+    'FOO' => 'BaR',
+    'TEST' => '1234',
+];