When pursuing goals, we commonly choose between going it alone versus teaming up together. In a field experiment (N=774 undergraduates), we tested the benefits of rewarding individual versus tandem goal pursuit. In a "standard-reward condition", we experimentally offered gym members an individual cash reward each day they visited the gym for four weeks. Participants in a "tandem-reward condition" could earn the same reward, but only if they surmounted an extra hurdle-they had to visit the gym with a friend. Although this additional requirement made it more difficult for participants in the tandem-reward condition to earn equivalent incentives, participants with this extra hurdle visited the gym about 35% more frequently than those earning a standard reward. A follow-up survey suggests that tandem rewards provide non-monetary incentives that change behavior, including increased accountability and enjoyment. Our findings illustrate the advantages of making desired behaviors social to promote follow-through.