In all three of the Toy Story movies, Andy was never referred to using his last name. There is only one place that mentions Andy's last name, out of all the movies and it was on Toy Story 3. When the toys tried to get Andy to play with them by calling his cell phone and "Operation Playtime" didn't work, Woody walked over to the message board to look at an old pic, when he lifted a piece of paper, he revealed an award made out to Andy Davis. The only time his last name was ever mentioned.

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