Sustainable transport modes, such as walking and cycling, have great benefits but the uptake is decreasing in Vietnam due to motorisation. Individual perceptions of travel and wider mobility cultures are increasingly seen as an important aspect in shaping travel patterns, in particular active travel. The understanding of this in youth active travel in Vietnam is not clear. The aim of this study is to understand how social factors and the physical environment influence adolescent active travel in Ho Chi Minh City (HCMC). A survey in HCMC targeting adolescents aged 11–16 (n = 525) across nine districts around the city centre was conducted. We adapted a comprehensive conceptual framework of active travel behaviour in the context of data availability and the study area. We also included variables pertaining weather, traffic safety, street vendors and road accident experiences, which are more relevant in powered two-wheeler (PTW) traffic saturated, tropical cities in a South East Asian setting. The results show positive association between favourable built environments (obstruction free pathways, food attractions and tree cover), social interactions (peer groups, parents and neighbourhoods) and negative association with traffic, air pollution and prior accident experiences. The findings highlight the importance of considering the interrelations of variables, whilst also identifying future research directions. Policy makers in HCMC, or in similar cities, should consider developing intervention strategies to improve the attractiveness of active travel.