Parenting stress has been linked with negative outcomes for parents and their infants (e.g., parental depression, negative parenting behaviors, poor attachment). Racial/ethnic minority adolescent mothers have increased risk for experiencing parenting stress compared to their White counterparts. Little is known about the changes in parenting stress over time for this population. Growth mixture modeling (GMM) was conducted to determine the growth trajectory classes of 185 African American and Latina/Hispanic adolescent mothers over 2 years. Risk and protective factors (e.g., maternal depression, social support, self-esteem) were examined to determine their influence on parenting stress trajectories. Three distinct trajectories of parenting stress were found: low stable stress (40.90%), decreasing stress (35.78%), and high stable stress (23.28%). Lower maternal depression (OR = 2.35), higher self-esteem (OR = 1.29), lower perceived social support from family (OR = 0.53) and higher perceived support from friends (OR = 1.65) predicted placement into the low stable parenting stress group over the high stable parenting stress group. Adolescents living with family (OR = 2.74) and Latina race/ethnicity (OR = 2.78) also served as predictors of placement into the low stable parenting stress group. Higher self-esteem (OR = 1.66) predicted placement into the decreasing parenting stress group over the high stable parenting stress group. These findings highlight the importance of perceived peer support by adolescent mothers, regardless of their support family support (e.g., living at home and receiving child care). Considering developmental factors such as peer relationships may be important when working with adolescent mothers.