diff --git a/src/CompletionProvider.php b/src/CompletionProvider.php
index 44cf5b8..2dba373 100644
--- a/src/CompletionProvider.php
+++ b/src/CompletionProvider.php
@@ -246,8 +246,10 @@ class CompletionProvider
             // Collect all definitions that match any of the prefixes
             foreach ($this->index->getDefinitions() as $fqn => $def) {
                 foreach ($prefixes as $prefix) {
-                    if (substr($fqn, 0, strlen($prefix)) === $prefix && $def->isMember) {
-                        $list->items[] = CompletionItemFactory::fromDefinition($def);
+                    if (substr($fqn, 0, strlen($prefix)) === $prefix && 
+                        $def->isMember &&
+                        $def->isVisible($prefix, $prefixes[0], $node)) {
+                        $list->items[] = CompletionItem::fromDefinition($def);
                     }
                 }
             }
diff --git a/src/Definition.php b/src/Definition.php
index 9ea27f9..4b6239d 100644
--- a/src/Definition.php
+++ b/src/Definition.php
@@ -133,4 +133,33 @@ class Definition
             }
         }
     }
+   
+    /**
+     * Checks the definition's visibility.
+     * @return bool
+     */
+    public function isVisible(string $match, string $caller, \Microsoft\PhpParser\Node $node): bool
+    {        
+        $ancestor = $node->getFirstAncestor(\Microsoft\PhpParser\Node\MethodDeclaration::class);        
+        
+        if ($ancestor) {
+            if ($match !== $caller && $this->isPrivate()) {
+                return false;
+            }
+        } else if ($this->isProtected() || $this->isPrivate()) {
+                return false;
+        }
+        
+        return true;
+    }
+
+    private function isPrivate(): bool
+    {
+        return 'private' === substr($this->declarationLine, 0, 7);
+    }
+
+    private function isProtected(): bool
+    {
+        return 'protected' === substr($this->declarationLine, 0, 9);
+    }
 }