The increased prevalence of media multitasking among adolescents has raised concerns that media multitasking may cause attention problems. Despite cross‐sectional evidence of the relationship between media multitasking and attention problems, no study has yet investigated this relationship longitudinally. It is therefore unclear how these two variables are related. Two 3‐wave longitudinal studies with 3‐ and 6‐month time lags were conducted. In total, 2,390 adolescents aged 11–16 provided data on media multitasking and attention problems. Findings from random intercept autoregressive cross‐lagged models suggest that media multitasking and attention problems were strongly related between individuals. Empirical evidence for a potential detrimental long‐term effect of media multitasking on attention problems was only found among early adolescents but not among middle adolescents.