This study investigated the effects of pairing based on English proficiency and gender on high school students’ speaking task performance. A total of 16 high school students - 4 female advanced, 4 female intermediate, 4 male advanced, and 4 male intermediate learners - performed two information gap tasks spotting differences between two pictures, once with a same-level learner and once with a different-level learner. Their performance was analyzed in terms of degree of task completion, amount of utterances and fluency. The results showed (a) advanced level learners performed the task more accurately, more fluently, and in higher length when they were paired with advanced level learners than paired with lower level learners, although the differences were not significant; (b) For intermediate level learners, male students demonstrated a better performance when paired with higher level learners, but female students performed better when paired with the same level learners. The findings are discussed with regard to more feasible and more effective ways of grouping for pair work in high school English classes.