What size baseball glove do you get for a 12 year old?

This depends on the position he plays. If he is a middle infielder (Shortstop or Second Base), you would want to get him a smaller glove to improve transfer of the ball from the glove to his throwing hand - about 9-10 in. If he plays outfield, the his glove should be much bigger to improve catching ability. This is about 11-12 inches. For a first baseman, buy a first baseman's glove (it will say on the tag) that is about 12 inches or longer. Third baseman's gloves should be about 11 inches. A catchers mitt is basically any catcher's mit you can hold up. Pitcher's should be around 10-11 inches with a thick web (pocket). If your player has never played before, he will probably be playing second base or outfield, and for him a large glove is recommended. For the average 13-year-old, a 9-12 inch glove is proper.