An extensive body of research has explored the effects of parental monitoring on adolescent outcomes, but studies consistently find substantial discrepancies between parent and adolescent reports of different monitoring behaviors. Little research has examined whether parents and adolescents are more or less discrepant when reporting on parents’ rules or solicitation for different adolescent problem and health risk behaviors and few studies have explored potential explanatory variables to explicate individual variability in parent-adolescent discrepant reporting. To address this gap in the literature, the current study examined discrepancies in mother-adolescent reports of family rules and solicitation across five distinct adolescent behaviors: personal behaviors and four different risk behaviors (alcohol-related, cyber, over- and under-eating). Participants were 143 mother-adolescent dyads (Adolescent M age = 14.42, SD = 1.73, range = 12–18, 81 % white, 60 % female). Mean-level discrepancies between maternal and adolescent reports significantly differed by category of adolescent behavior and also varied as a function of reported parental monitoring behavior (rules vs. solicitation). Discrepancies in mother-adolescent reports of behavior-specific rules and solicitation were positively associated with discrepancies in mother and adolescent judgments of the harmfulness of the activities. The results demonstrate that discrepancies in mother-adolescent reports of family process differ by category of adolescent behavior and may be undergirded by differences in mother and adolescent informational assumptions about the potential harm involved with different activities.