A widespread concern in society is that adolescents experience an increased inability to concentrate and sustain attention because they are continuously distracted by social media. The current experience sampling method (ESM) study examined whether adolescents who use more social media than their peers experience more distraction (between-person association), whether social media use (SMU) and distraction cofluctuate within adolescents (momentary within-person associations), and to what extent this within-person association differs from person to person (person-specific associations). With a sample of 383 adolescents (M age = 14.11), who together completed 35,099 ESM surveys (73% compliance), we found both a positive between-person association (β = .31) and a positive momentary within-person association (β = .12) of SMU with distraction. The momentary within-person association differed from adolescent to adolescent: While SMU and distraction were positively associated among 82.5% of all adolescents, they were not associated among 15.7% of the adolescents, and negatively associated among 1.8% of the adolescents. Additional analyses on the direction of the effect showed that the within-person effect of SMU on subsequent levels of distraction was somewhat stronger (β = .05) than the effect of distraction on subsequent levels of SMU (β = .03).