AimsThe U.S. Public Health Service Clinical Practice Guideline on treating tobacco use and dependence recommends providing advice to quit to every tobacco user seen in a healthcare setting. However, the mechanism through which counseling encourages patients to quit has not been adequately studied. This study tests whether the association between receiving healthcare provider counseling and desire to quit is accounted for by negative health and psychosocial outcome expectancies of smoking. MethodsData were collected online from 721 adult smokers who had seen a healthcare provider in the past 12 months. Associations between counseling to quit, negative outcome expectancies of smoking, and desire to quit were tested, as well as whether outcome expectancies and desire to quit differed by type of counseling (counseling only vs. counseling plus assistance) and level of smoking. ResultsBivariate associations indicated a stronger desire to quit among patients receiving counseling, particularly when it included healthcare provider assistance to quit. SEM results indicated that the association between counseling and desire to quit was fully accounted for by patients' negative health and psychosocial outcome expectancies for smoking. These associations were found across levels of smoking in the case of health expectancies, but were limited to moderate and heavy smokers in the case of psychosocial expectancies. ConclusionResults suggest that the time devoted to counseling patients about smoking should include providing some assistance to quit, such as recommending a product, prescription or program. Regardless of smoking level, this counseling should incorporate techniques to elicit patients' negative health and psychosocial expectancies of smoking.