Gender differences in competition and sabotage

•Analysis of gender differences in a real effort two-player tournament in the lab.•No performance differences between males and females.•Males sabotage more than females, leading to a higher winning probability.•If gender of opponent is known, males enhance performance.•Reaction of males is more pronounced when competing with a female opponent.

We study the differences in behavior of males and females in a two-player tournament with sabotage in a controlled lab experiment. Implementing a real-effort design and a principal who is paid based on the agent's output, we find that males and females do not differ in their performance in the real effort task but in their choice of sabotage. Males select significantly more sabotage, leading to an, on average, higher winning probability but not to higher profits. If the gender of the opponent is revealed before the tournament, males increase their performance in the real-effort task especially if the opponent is female. The gender gap in sabotage is persistent. We discuss possible explanations for our findings and their implications.