Planning before quitting smoking is widely believed to be beneficial and is usually recommended in cessation counseling, but there is little evidence on the efficacy of specific planning activities. Using data from 1140 respondents who reported quit attempts at Wave 8 of the ITC 4-Country Survey, we analyzed use of 8 specific planning strategies before (5) and after (3) implementation of a quit attempt, in relation to cessation outcomes, delay in implementation of the attempt, and recent quitting history. Most participants reported some planning both before and after quitting, even among those reporting quitting 'spontaneously.' Younger smokers, those who cut down before quitting, and users of stop-smoking medication were more likely to report planning. Those who planned prequit were also more likely to plan postquit. Unexpectedly, we found no clear benefit of planning on short-term (1 month) cessation outcomes, whereas one prequit strategy (practicing not smoking) was negatively related to outcome. There was evidence for a predicted moderating effect of recent quitting experience on planning for the prequit task 'practice replacement strategies.' This predicted quit success among those with multiple quit attempts in the past year, but failure among those without. This finding suggests that the quality of planning may be critical. More research, particularly on the moderating effect of quit experience, and where measures of planning are collected before outcomes become evident, is needed before clear recommendations can be made on the utility of various forms of planning for the success of quit attempts.