Background: Significant proportions of school children in the UK do not meet the minimum recommended daily requirements of 60-min moderate-intensity physical activity. Beyond taught classes, playtimes offer the opportunity for children to play and be physically active. Painted markings are one recent addition to school playgrounds that are inexpensive and have been shown to stimulate increased levels of physical activity among children during playtimes. Playground markings and supportive playground assistants can act as cues to increase physical activity. Purpose: While evidence exists to support the impact of playground markings on the levels of physical activity, no attempts have been made to assess the effects of playground markings on important indicators of psychological health such as self-esteem and physical self-concept. The way children view themselves from a physical perspective is likely to impact their future engagement in sport and physical activities. Given that the levels of physical activity have been found to be related to physical self-perceptions and self-esteem, and playground markings appear to facilitate increased physical activity, this study aimed to evaluate the effects of installing playground markings and training playground assistants on children's physical self-perceptions. Participants and setting: Participants were 218 primary school children (117 girls and 101 boys) aged 10 and 11 years. Informed consent was gained from all schools, and parents were given the choice to withdraw their child from the project before commencement of testing. Twelve schools received playground markings, while four further schools acted as controls. Playground assistants were trained to help facilitate use of markings by children. Playground markings consisted of painted lines and boxes. Data collection: The participants completed the Children and Youth Physical Self-Perception Profile under the supervision of trained research assistants. The behaviour of the children was also observed during the morning and lunch playtime periods prior to the installation of playground markings and again 8 months after installation. The System for Observing Children's Activity and Relationships during Play was used to assess playtime behaviour with 242 observations in total undertaken. Every sixth child to enter the playground was randomly observed for 10 min. Data analysis: Mixed-model ANOVAs were used to test for differences in physical self-perceptions of the children on the basis of intervention and over time. Percentage changes in observed physical activity and pro-social behaviours were calculated to determine differences between schools that received markings and those that did not. Findings: No significant differences were found in physical self-perceptions on the basis of intervention or over time. However, boys did report significantly higher perceptions of sport competence, physical conditioning, physical strength and physical self-worth than girls. Observed physical activity was found to increase by 7.5% in schools that received markings as opposed to a 7.7% decline in control schools. In addition, pro-social behaviours were found to increase by 6.7% following the installation of playground markings. Conclusion: These findings indicate that while playground markings can facilitate increased physical activity during playtimes, this does not translate into enhanced self-perceptions in children when evaluated 8 months after intervention.