|Book Appearance?||Yes (Mentioned only)|
Barbara is an old friend of Susan, who was only heard in Dog Days when Greg wanted Susan to take his picture with Heather Hills. As she was about to take it, she received a phone call from Barbara and was on the phone for 5 minutes. When they finished talking, Susan snapped Greg's photo, but Heather had to change her pool because her lifeguard shifting for this pool was over. Susan did take a picture, but by that time some other lifeguard had come.
- Diary of a Wimpy Kid: Dog Days (Mentioned only)
- There is a weather forecaster working for a news channel in Rodrick Rules who is named Barbara.