diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d4757ce..f3207344 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 
 - Read autoload-dev psr-4 namespaces for gacela make commands.
 - Cache default resolved gacela class.
+- Allow optional project namespace on class name finder rules.
 
 ### 0.26.0
 #### 2022-10-01
diff --git a/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithModulePrefix.php b/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithModulePrefix.php
index f57da024..1ea336be 100644
--- a/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithModulePrefix.php
+++ b/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithModulePrefix.php
@@ -10,9 +10,17 @@ final class FinderRuleWithModulePrefix implements FinderRuleInterface
 {
     public function buildClassCandidate(string $projectNamespace, string $resolvableType, ClassInfo $classInfo): string
     {
+        if ($projectNamespace !== '') {
+            return sprintf(
+                '\\%s\\%s\\%s',
+                trim($projectNamespace, '\\'),
+                $classInfo->getModuleName(),
+                $classInfo->getModuleName() . $resolvableType
+            );
+        }
+
         return sprintf(
-            '\\%s\\%s\\%s',
-            trim($projectNamespace, '\\'),
+            '\\%s\\%s',
             $classInfo->getModuleName(),
             $classInfo->getModuleName() . $resolvableType
         );
diff --git a/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithoutModulePrefix.php b/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithoutModulePrefix.php
index b332a163..227f882f 100644
--- a/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithoutModulePrefix.php
+++ b/src/Framework/ClassResolver/ClassNameFinder/Rule/FinderRuleWithoutModulePrefix.php
@@ -10,9 +10,17 @@ final class FinderRuleWithoutModulePrefix implements FinderRuleInterface
 {
     public function buildClassCandidate(string $projectNamespace, string $resolvableType, ClassInfo $classInfo): string
     {
+        if ($projectNamespace !== '') {
+            return sprintf(
+                '\\%s\\%s\\%s',
+                trim($projectNamespace, '\\'),
+                $classInfo->getModuleName(),
+                $resolvableType
+            );
+        }
+
         return sprintf(
-            '\\%s\\%s\\%s',
-            trim($projectNamespace, '\\'),
+            '\\%s\\%s',
             $classInfo->getModuleName(),
             $resolvableType
         );