Higher working memory capacity (WMC) supports performance on a wide variety of complex cognitive and academic activities (Barret, Tugade, & Engle, 2004). However, a growing body of research demonstrates that higher WMC can have disadvantages—leading individuals to employ complex performance strategies that are less optimal for a given task (cf. DeCaro & Beilock, 2010). We examine this possibility in the domain of insight problem solving. Participants (N=84) completed Matchstick Arithmetic problems thought to either rely on controlled search and retrieval processes (non-insight problems) or diverging from known mathematical constraints (insight problems). Consistent with a large body of research on WMC, higher WMC was associated with higher non-insight problem accuracy. However, higher WMC led to significantly worse insight problem-solving. Although higher WMC supports complex problem-solving strategies, relying on these may lead individuals to miss associatively-driven solutions that are important for insight.