There is limited knowledge about key factors that enable adolescent girls with a low socioeconomic position (SEP) to adopt a healthy lifestyle. This paper aims to better understand the complexity of addressing health behaviour of adolescent girls with a low SEP by gaining insights into (i) the perspectives of adolescent girls with a low SEP (n = 26) on a healthy lifestyle, (ii) how to develop health promotion that fits these girls’ daily realities, by using participatory action research (PAR) in which girls developed health promotion materials. The study offers an understanding of girls’ daily lives and how health promotion could be improved.