The aim of this study is to investigate associations of screen-time and physical activity (PA) with self-efficacy for PA, intrinsic motivation to PA and health-related quality of life (HRQoL) in Colombian schoolchildren from socioeconomically disadvantaged neighborhoods, and to compare these variables among children with normal-weight (NW), overweight (OW) and obesity (OB).In 678 schoolchildren (age 10-14 years) screen-time (TV, video games, computer) and number of days being physically active ≥ 60 minutes were self-reported. Multi-item scales were used to assess self-efficacy to PA and intrinsic motivation to PA. The KIDSCREEN-27 was used to assess HRQoL.Screen-time was associated with HRQoL in the school/learning environment dimension. Number of days being physically active was associated with self-efficacy for PA, intrinsic motivation for PA and with HRQoL concerning physical well-being, autonomy/parent relation and social support/peers. Group differences were found for days being physically active (OW = 2.8 and OB = 2.7 vs. NW = 3.3) but not for screen-time (NW = 5.0, OW = 4.7 and OB = 5.7 hrs·d-1). OW and OB scored lower on intrinsic motivation to PA than NW (OW = 19.2 and OB = 17.9 versus NW = 20.1). All 3 groups differed in physical well-being scores (NW = 50.3, OW = 48.1, OB = 40.6, P < .001).Schoolchildren with overweight and obesity from socioeconomically disadvantaged neighborhoods need additional motivational support to perform health-enhancing PA to experience higher physical well-being.