diff --git a/src/Symfony/Component/HttpClient/HttpClientTrait.php b/src/Symfony/Component/HttpClient/HttpClientTrait.php
index 2431e806b0..cf439c6ff0 100644
--- a/src/Symfony/Component/HttpClient/HttpClientTrait.php
+++ b/src/Symfony/Component/HttpClient/HttpClientTrait.php
@@ -377,6 +377,10 @@ trait HttpClientTrait
             throw new InvalidArgumentException(sprintf('Invalid "base_uri" option: host or scheme is missing in "%s".', implode('', $base)));
         }
 
+        if (null === $url['scheme'] && (null === $base || null === $base['scheme'])) {
+            throw new InvalidArgumentException(sprintf('Invalid URL: scheme is missing in "%s". Did you forget to add "http(s)://"?', implode('', $base ?? $url)));
+        }
+
         if (null === $base && '' === $url['scheme'].$url['authority']) {
             throw new InvalidArgumentException(sprintf('Invalid URL: no "base_uri" option was provided and host or scheme is missing in "%s".', implode('', $url)));
         }
diff --git a/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php b/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php
index bce71ce823..f3ece3c140 100644
--- a/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php
+++ b/src/Symfony/Component/HttpClient/Tests/HttpClientTraitTest.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\HttpClient\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\HttpClient\Exception\InvalidArgumentException;
 use Symfony\Component\HttpClient\HttpClientTrait;
 use Symfony\Contracts\HttpClient\HttpClientInterface;
 
@@ -120,6 +121,20 @@ class HttpClientTraitTest extends TestCase
         ];
     }
 
+    public function testResolveUrlWithoutScheme()
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URL: scheme is missing in "//localhost:8080". Did you forget to add "http(s)://"?');
+        self::resolveUrl(self::parseUrl('localhost:8080'), null);
+    }
+
+    public function testResolveBaseUrlWitoutScheme()
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Invalid URL: scheme is missing in "//localhost:8081". Did you forget to add "http(s)://"?');
+        self::resolveUrl(self::parseUrl('/foo'), self::parseUrl('localhost:8081'));
+    }
+
     /**
      * @dataProvider provideParseUrl
      */