OBJECTIVES: Regulatory focus theory proposes 2 self-regulatory orientations: promotion focus - related to achieving aspirations and positive outcomes - and prevention focus - related to fulfilling responsibilities and preventing negative outcomes. The investigation examined whether regulatory focus and proximity to goal weight moderated the effectiveness of a weight-loss maintenance intervention. METHODS: Participants who lost >/=10% of their weight were assigned to guided or self-directed treatments and completed regulatory focus and weight goal measures. RESULTS: Across treatment groups, people who were more promotion-focused had better 2-year maintenance rates (defined as regain <25%) than people who were less promotion-focused, especially if far from their goal weight (.59 versus .44). In the guided group, people who were more prevention-focused had better maintenance rates than people who were less prevention-focused if closer to their goal weight (.69 versus .42), but poorer maintenance rates if farther from their goal (.36 versus .72). In the self-directed group, prevention focus was unrelated to maintenance. CONCLUSIONS: Regulatory focus and proximity to goal weight moderated intervention effectiveness. Maintenance may be enhanced by tailoring treatments to regulatory focus and goal weight (eg, prevention-focused people far from their goals may need extra weight-loss support before focusing on maintenance).