Objectives: To examine the motivational predictors of the smoking cessation process at the between-persons and within-persons levels.

Methods: Mediation analyses were conducted on self-report data (N = 236) that were collected using interval contingent sampling over a 39-day study period.

Results: There was a high rate of attrition, as nearly 50% of participants were lost to follow-up. There were credible indirect effects of autonomous self-regulation on smoking behavior on the next day and seven-day abstinence through perceived competence and medication use. At the between-persons level, these models explained 17% of the variance in smoking behavior on the next day and 31% of the variance in seven-day abstinence; at the within-persons level, these estimates were 39% and 57%, respectively.

Conclusions: Day-to-day changes in autonomous self-regulation, perceived competence, and medication use are important initiators of the smoking cessation process.Practice implicationsSmokers might be more likely to make a quit attempt if practitioners “tune into” the day-to-day fluctuations of their patients’ motivation for stopping smoking, perhaps using an electronic platform to assess and compare smokers’ current reports to their previous experiences. Such “motivational attunement” can afford practitioners an opportunity to provide need support when patients are willing and able to initiate a quit attempt. © 2023 Elsevier B.V.