Imagery is one of the most widely-researched topics in sport psychology. Recent research has been focused on how imagery works and how to apply it to have the greatest possible performance effect. However, the amount of imagery needed to produce optimal effects has been under-researched, particularly in relation to the PETTLEP model of imagery (Holmes & Collins, 2001). This study examined the effects of differing frequencies of PETTLEP imagery on bicep curl performance, using a single-case design. Following a baseline period, participants completed PETTLEP imagery 1×/week, 2×/week, or 3×/week in a counterbalanced pattern. Results indicated that PETTLEP imagery had a positive effect on performance. In addition, as the frequency of imagery increased, a larger performance effect was apparent. These results support the notion that PETTLEP imagery can lead to strength gains if performed at least 1× per week, but that completing imagery more frequently may be more effective.