Objective: Previous research (Webb, Simmons, & Brandon, 2005) suggested that smokers' reactions to self-help materials were more positive if they believed that the materials had been personally tailored to their individual characteristics and if they held expectancies that tailored interventions are superior to standard, or generic, interventions. The authors' objective in the current study was to replicate and extend this research by testing the efficacy expectancy priming before intervention delivery. Design: In a 2 × 2 factorial experiment, 210 smokers (M = 23 cigarettes/day) recruited from the community (62% female; 92% Caucasian; mean age = 49) were randomly assigned to 1 of 4 conditions: placebo-tailored intervention/no priming, placebo-tailored intervention/priming, standard intervention/no priming, or standard intervention/priming. The tailoring-related expectancies of participants' in the priming conditions were primed before they were presented with the respective intervention booklets. Main Outcome Measures: Content evaluations, readiness to quit smoking, cessation self-efficacy, smoking-related knowledge, and progress toward quitting (behavior changes). Assessments occurred by mail at baseline and at 1-month postintervention. Results: Similar to the earlier study, the placebo-tailored booklets produced superior evaluations and smoking-related cognitive and behavioral changes. Moreover, the pretreatment expectancy priming successfully altered participants' tailoring-related expectancies and also produced superior evaluations and outcomes. Conclusion: Findings support a causal role of tailoring-related expectancies on the efficacy of tailored interventions and suggest that interventions can be enhanced via expectancy priming. © 2007 American Psychological Association.