Moderate‐quality evidence shows that nursing interventions slightly increased the number of adults who quit smoking compared with usual care (on average, 157 vs 122 quit smoking per 1000 people). Reviewers found no clear evidence that trials using higher‐intensity interventions (initial contact lasted longer than 10 minutes) had larger treatment effects. Components of the nursing interventions varied considerably across trials (including self‐efficacy programs, counseling, advice, education, and motivational enhancement), and most trials did not report the components of usual care, making it difficult to identify whether any specific components were more beneficial than others. In addition, only 50% of trials specified that self‐reports of abstinence were consistently confirmed biochemically, and trials did not report reductions in smoking or the incidence of adverse events.