Introduction Social networking sites such as Instagram have provided young people with unprecedented opportunities for social comparison, and such behaviour can have implications for identity development. Although initial evidence suggests that there may be developmental differences in terms of how such behaviour informs identity development during adolescence and emerging adulthood, all previous research has been conducted in highly individualistic cultural contexts (i.e., the UK and the US). Method To shed further light on these possible developmental differences and to determine whether results replicate amongst young people from more collectivist cultural contexts, cross‐sectional survey data were collected from 1,085 (M age = 18.87, SD = 2.57; Female = 77.8%) adolescents and emerging adults in Romania and Serbia between December 2019 and March 2020. The relationships between social comparisons of ability and opinion on Instagram and three key identity processes (i.e., commitment, in‐depth exploration, and reconsideration of commitment) were then examined. Result Hierarchical multiple regression analyses identified significant age differences in terms of how social comparisons of ability and opinion on Instagram associated with identity commitment and in‐depth exploration. Furthermore, possible cultural differences were identified in terms of how social comparisons of opinion on Instagram associated with the identity processes. Conclusion Overall, results suggest that whilst social comparisons on Instagram can elicit self‐focus and prompt further exploration, developmental and cultural factors may influence how such behaviour informs identity development during adolescence and emerging adulthood.