Social situations can, at times, have a detrimental influence on behavior (e.g., exposure to supermodels can make people dumb, certain social situations can prompt excessive alcohol consumption). Gaining control over such effects can be difficult because the situational influence often occurs outside conscious awareness. The present research investigates whether forming if-then plans or “implementation intentions” (Gollwitzer, 1999) can help people to strategically prevent unwanted social influences. Two experiments found that priming social categories (e.g., supermodels, Experiment 1) or social goals (e.g., socializing, Experiment 2) can have a detrimental impact on participants’ general knowledge (Experiment 1) and mental readiness to drink (Experiment 2), respectively. However, both experiments also showed that forming implementation intentions designed to ensure the effective mobilization of resources (Experiment 1) or to ignore temptation (Experiment 2) prevented social primes from influencing behavior. These findings suggest that if-then planning affords strategic control over unwanted social influences on action.