Previous research using collaborative mobile augmented reality games in science education revealed that such games can be used to promote learner engagement and have found that engagement in such mobile games is related to flow. This study investigated whether player's flow experience differed by achievement track, gender, or gender composition of working groups. In an urban school district, 202 students from two eighth-grade science classes participated in a collaborative mobile science game. Data included a self-report survey collected after the game that measured player's flow experience. Using a regression model, the relationship of flow experience with achievement track and gender was explored while controlling for group composition and teacher effects. The study found that gender was related to flow experience; specifically, girls reported higher flow experience scores (d = 0.30). Flow experience did not have a statistically significant relationship with achievement track showing that the activity engaged all observed students similarly.