diff --git a/src/main/java/org/verapdf/pd/font/opentype/OpenTypeFontProgram.java b/src/main/java/org/verapdf/pd/font/opentype/OpenTypeFontProgram.java
index bf15b9f2..6d8ce927 100644
--- a/src/main/java/org/verapdf/pd/font/opentype/OpenTypeFontProgram.java
+++ b/src/main/java/org/verapdf/pd/font/opentype/OpenTypeFontProgram.java
@@ -120,7 +120,7 @@ public boolean containsCID(int cid) {
 
     @Override
     public String getGlyphName(int code) {
-        return this.font.getGlyphName(code);
+        return this.font != null ? this.font.getGlyphName(code) : null;
     }
 
     /**