diff --git a/src/Analyser/Analyser.php b/src/Analyser/Analyser.php
index 2ad7ae6b..e3fa6024 100644
--- a/src/Analyser/Analyser.php
+++ b/src/Analyser/Analyser.php
@@ -540,7 +540,12 @@ private function collectPhpFiles(array $layers, array $scanPaths, array $skipPat
         $files = [];
 
         foreach ($this->scanPaths($layers, $scanPaths) as $layerPath) {
-            $fullPath = rtrim($this->basePath, '/') . '/' . ltrim($layerPath, '/');
+            $isAbsolute = str_starts_with($layerPath, '/') || (strlen($layerPath) >= 2 && $layerPath[1] === ':');
+            $fullPath   = $this->normalisePath(
+                $isAbsolute
+                    ? $layerPath
+                    : rtrim($this->basePath, '/') . '/' . ltrim($layerPath, '/')
+            );
 
             if (is_file($fullPath)) {
                 if (str_ends_with($fullPath, '.php') && ! $this->isSkipped($fullPath, $skipPaths)) {
diff --git a/src/Rule/Rules/Composer/Psr4SourcePathsRule.php b/src/Rule/Rules/Composer/Psr4SourcePathsRule.php
index 2922c830..75bf1f7f 100644
--- a/src/Rule/Rules/Composer/Psr4SourcePathsRule.php
+++ b/src/Rule/Rules/Composer/Psr4SourcePathsRule.php
@@ -16,6 +16,9 @@
 use function rtrim;
 use function sprintf;
 use function str_replace;
+use function str_starts_with;
+use function strlen;
+use function substr;
 use function trim;
 
 final readonly class Psr4SourcePathsRule implements ProjectRuleInterface
@@ -38,7 +41,7 @@ public function sourcePathsFor(string $basePath): array
             return $this->psr4PathResolver->paths($basePath);
         }
 
-        return $this->normalisePaths($this->sourcePaths);
+        return $this->normalisePaths($this->sourcePaths, $basePath);
     }
 
     public function evaluateProject(string $basePath, Architecture $architecture, array $skipPaths = []): ?RuleViolation
@@ -68,7 +71,7 @@ public function evaluateProject(string $basePath, Architecture $architecture, ar
         $autoloadPaths = $this->psr4PathResolver->paths($basePath);
         $missingPaths  = [];
 
-        foreach ($this->normalisePaths($this->sourcePaths) as $sourcePath) {
+        foreach ($this->normalisePaths($this->sourcePaths, $basePath) as $sourcePath) {
             if (! in_array($sourcePath, $autoloadPaths, true)) {
                 $missingPaths[] = $sourcePath;
             }
@@ -91,10 +94,20 @@ public function evaluateProject(string $basePath, Architecture $architecture, ar
      * @param list<string> $paths
      * @return list<string>
      */
-    private function normalisePaths(array $paths): array
+    private function normalisePaths(array $paths, string $basePath): array
     {
+        $normalisedBase = rtrim(str_replace('\\', '/', $basePath), '/');
+
         return array_map(
-            static fn(string $path): string => rtrim(str_replace('\\', '/', trim($path)), '/'),
+            static function (string $path) use ($normalisedBase): string {
+                $path = rtrim(str_replace('\\', '/', trim($path)), '/');
+
+                if ($normalisedBase !== '' && str_starts_with($path, $normalisedBase . '/')) {
+                    return substr($path, strlen($normalisedBase) + 1);
+                }
+
+                return $path;
+            },
             $paths
         );
     }
diff --git a/tests/Analyser/AnalyserTest.php b/tests/Analyser/AnalyserTest.php
index 77dd9d21..4dd24d40 100644
--- a/tests/Analyser/AnalyserTest.php
+++ b/tests/Analyser/AnalyserTest.php
@@ -434,6 +434,40 @@ public function testFilesForAnalysisIgnoresDirectorySymlinks(): void
         $this->assertStringEndsWith('/src/Foo.php', $this->normalisePath($files[0]));
     }
 
+    public function testFilesForAnalysisWithAbsoluteScanPath(): void
+    {
+        $basePath = $this->makeTempProject([
+            'index.php'   => '<?php namespace App; final class Index {}',
+            'src/Foo.php' => '<?php namespace App; final class Foo {}',
+        ]);
+
+        $architecture = Architecture::define()
+            ->layer('Source', 'src/');
+
+        $absoluteScanPath = $basePath . '/index.php';
+
+        $files = (new Analyser($basePath))->filesForAnalysis($architecture, [$absoluteScanPath]);
+
+        $this->assertCount(1, $files);
+        $this->assertStringEndsWith('/index.php', $this->normalisePath($files[0]));
+    }
+
+    public function testFilesForAnalysisWithRootRelativeScanPath(): void
+    {
+        $basePath = $this->makeTempProject([
+            'index.php'   => '<?php namespace App; final class Index {}',
+            'src/Foo.php' => '<?php namespace App; final class Foo {}',
+        ]);
+
+        $architecture = Architecture::define()
+            ->layer('Source', 'src/');
+
+        $files = (new Analyser($basePath))->filesForAnalysis($architecture, ['index.php']);
+
+        $this->assertCount(1, $files);
+        $this->assertStringEndsWith('/index.php', $this->normalisePath($files[0]));
+    }
+
     public function testFilesForAnalysisUsesPreResolvedLayersWhenProvided(): void
     {
         $basePath = $this->makeTempProject([
diff --git a/tests/Rule/Composer/Psr4SourcePathsRuleTest.php b/tests/Rule/Composer/Psr4SourcePathsRuleTest.php
index 5ceee621..6fc6151e 100644
--- a/tests/Rule/Composer/Psr4SourcePathsRuleTest.php
+++ b/tests/Rule/Composer/Psr4SourcePathsRuleTest.php
@@ -164,6 +164,32 @@ public function testNormalisesExplicitSourcePaths(): void
         $this->assertSame(['src', 'tests'], $psr4SourcePathsRule->sourcePathsFor($this->makeTempDir()));
     }
 
+    public function testPassesWhenAbsoluteSourcePathsExistInComposerPsr4Autoloads(): void
+    {
+        $basePath = $this->makeTempProject(<<<'JSON'
+{
+    "autoload": {
+        "psr-4": {
+            "App\\": "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "App\\Tests\\": "tests/"
+        }
+    }
+}
+JSON);
+
+        $psr4SourcePathsRule = new Psr4SourcePathsRule([$basePath . '/src', $basePath . '/tests']);
+
+        $this->assertNotInstanceOf(
+            RuleViolation::class,
+            $psr4SourcePathsRule->evaluateProject($basePath, Architecture::define())
+        );
+        $this->assertSame(['src', 'tests'], $psr4SourcePathsRule->sourcePathsFor($basePath));
+    }
+
     private function makeTempProject(string $composerJson): string
     {
         $basePath = $this->makeTempDir();