The current longitudinal study examined adolescent gender differences in the developmental changes and relational correlates of secrecy from parents. For 4 successive years, starting in the second year of junior high (mean age at Time 1 = 13.2 years, SD = 0.51), 149 male and 160 female Dutch adolescents reported on secrecy from their parents and the quality of the parent-child relationship. Latent growth curve modeling revealed a linear increase in secrecy, which was significantly faster for boys than for girls. Moreover, cross-lagged panel analyses showed clear concurrent and longitudinal linkages between secrecy from parents and poorer parent-child relationship quality in girls. In boys, much less strong linkages were found between poorer relationships and secrecy from parents. © 2010 American Psychological Association.