diff --git a/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDAbstractContentStream.java b/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDAbstractContentStream.java
index d57ab7699a4..94825a880f8 100644
--- a/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDAbstractContentStream.java
+++ b/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDAbstractContentStream.java
@@ -1556,6 +1556,14 @@ public void close() throws IOException
         {
             LOG.warn("You did not call endText(), some viewers won't display your text");
         }
+
+        // Release large data structures immediately so the GC can reclaim memory
+        // even if callers hold a reference to this COSDocument instance.
+        fontStack.clear();
+        nonStrokingColorSpaceStack.clear();
+        strokingColorSpaceStack.clear();
+        gsubWorkers.clear();
+
         outputStream.close();
     }