ParticipACTION is a Canadian physical activity communications and social marketing organization relaunched in 2007. The purpose of this study was to qualitatively investigate organizational capacity for physical activity promotion among Canadian organizations, and the influence of ParticipACTION on capacity five years after relaunch.Using a purposive sampling strategy, semi-structured telephone interviews were conducted with 44 key informants representing national, provincial, and local organizations with a mandate to promote physical activity. Interview data were analyzed using a thematic analytic approach.Organizational capacity in terms of partnerships and collaborations, and the general climate for physical activity promotion have improved since ParticipACTION's relaunch. Although financial resources reduced the ability of organizations to fulfil their mandates, internal factors such as skilled employees and sponsorships, and external factors such as technological improvements in communication and information sharing helped to offset this strain. There were mixed feelings on ParticipACTION's contribution to capacity. While ParticipACTION has brought more attention to inactivity, this was perceived as a complement to work already taking place. While some organizations perceived ParticipACTION's relaunch as competition to funding and access to popular media, others found it as an opportunity to co-brand social marketing campaigns, utilizing ParticipACTION's products and reputation.According to participants, organizational capacity to promote physical activity in Canada has increased since 2007 in subtle but important ways because of a strong climate for physical activity promotion, skilled employees, and information sharing technology. Organizational capacity changes were minimally attributed to ParticipACTION.