OBJECTIVE To examine the association between gestational weight gain (GWG) and interpregnancy weight change (IPWC) in adolescent mothers (younger than 20 years), and to determine if this association differs from adult women (aged 20-35 years). METHODS Retrospective cohort study. METHODS We included 3055 adolescents and 17,090 adult women with singleton pregnancies recorded in the Nova Scotia Atlee Perinatal Database with a subsequent pregnancy occurring between 2003 and 2014. METHODS GWG in the first pregnancy was categorized as below, within, or above the current Institute of Medicine recommendations. IPWC was defined as the difference between the prepregnancy weights of the 2 pregnancies. Analyses were adjusted for parity, body mass index in the first pregnancy, and time between pregnancies. RESULTS Relative to adolescents with GWG within the recommendations, those who gained below had a 2.7 kg (95% confidence interval [CI], 1.4-3.9) lower mean IPWC whereas those who gained above had a 4.2 kg (95% CI, 3.3-5.1) higher mean IPWC. Smaller differences in IPWC between GWG categories were observed in adult women; relative to those with GWG within the recommendations, adults who gained below had a 1.3 kg (95% CI, 0.9-1.7) lower mean IPWC and those who gained above had a 2.9 kg (95% CI, 2.6-3.2) higher mean IPWC. CONCLUSIONS Mean IPWC differed across GWG categories and the differences were greater in adolescents than in adult women. This difference should be considered when assessing whether specific GWG recommendations are needed for adolescents.