OBJECTIVES: This study focused on lapse shortly after an attempt to quit smoking. Ecological momentary assessment (EMA) studies have mapped real-time situational factors that induce lapses in everyday life. However, the possible role of nonsmoking intention is disregarded in the dynamic context of daily life, whereas intention plays a key role in behavior change and shifts during smoking cessation. This study therefore aimed to capture the influence of intention on lapse, next to the known risk factors of negative affect, low self-efficacy, craving, positive outcome expectations towards smoking (POEs), being around smokers, and stress. It is hypothesized that scores on these factors shift during the day, especially shortly after quitting, which may induce lapse. Based on behavioral explanation models, intention is hypothesized to mediate the influence of the mentioned factors on lapse.METHODS: An EMA study was conducted among 49 self-quitters in the first week of smoking cessation.RESULTS: Generalized Linear Mixed Model regression analyses revealed that low nonsmoking intentions, low self-efficacy, and being around smokers (estimates were, respectively, -0.303, -0.331, and 2.083) predicted lapse. Nonsmoking intention partially mediated the influence of self-efficacy on lapse. Nonsmoking intention was predicted by not being around smokers, high self-efficacy, and low POEs (estimates were, respectively, -0.353, 0.293, and -0.072).CONCLUSIONS: This small-scale EMA study confirms the importance of nonsmoking intention on lapse, next to self-efficacy and being around smokers. It adds insights into the mediating role of intention on the relationship between self-efficacy and lapse, and into the predictors of nonsmoking intention.