Giles is a character that mentioned and appeared in Old School. He was Frank's childhood best friend. Frank said when he was a kid at Greg's age, he and his best friend, Giles, would use their imaginations and play all day in the woods. Then he said that today's parents were overprotective and when he was a kid, he and Giles roamed around and they never bothered to tell their parents where they are going. But his mom told him that it was a LOT safer back in those days, and now it's too dangerous to for kids to be without adult supervision when they are on their own. He said that when he was in middle school with his best friend, Giles, they had buried stuff all over town so that they could fight their way out if they are cornered. Frank said he and Giles had raided the kitchen drawer for silverware, and that's why they stashed all over the neighbourhood. But then his mother realized that her forks and knives were missing, she told the boys to dig them all up and bring them back. After that, he and Giles got their hands on plastic utensils. But they got an argument whether or not a spork could be use for self-defense. After that, things turn ugly when Frank poke him with a spork on his butt. Giles told his mom about what Frank did and he showed her the spork marks to prove it. Greg guessed that in those must've been a different times, because Giles's mom bent Frank over her knee and ready to spank him. Greg mentioned that the problem with putting too much stock in the old days. He remembered all the GOOD stuff, but he forget about the time that you got spanked by your best friend's mom. Greg was planning that he could relax and read comic books on the couch all day, but Frank told him he should take advantage of all the "foot traffic". He said that when he was a kid, he and Giles opened a lemonade stand and they earned enough money to buy each of them a skateboard. It is currently unknown what his relationship with Frank is like in present time, but it can be assumed that they split ways.
- Diary of a Wimpy Kid: Old School (First and only appearance, flashback)
- Giles must be Frank's age now as an adult.
- It is unknown how he looks like as an adult.