Despite the importance of persuasion knowledge (PK) for understanding how individuals cope with persuasion, there is little research addressing how PK can be developed and sustained. We explore dispositional PK (consumers’ confidence in their knowledge about marketer agents’ persuasion tactics) and coping skills (i.e., critical thinking about media: skepticism, understanding bias, scrutinizing source) among families in Jamaica after an intervention and at a delay. We randomly assigned 62 mother–adolescent pairs to an intervention (two workshops) or control group: all participants completed questionnaires four times (baseline, after Workshop 1, after Workshop 2, 10 to 11 weeks after Workshop 2). Workshop 1 provided information related to PK, and then families completed “subvertising” homework. Subvertising allows audiences to critically evaluate media content and to construct subversive narratives, often through parody. In Workshop 2, families discussed and presented their subvertisements. Results of the multivariate analyses of variance (MANOVAs) revealed time × condition interaction effects for skepticism (mothers), bias (adolescents), and source (adolescents), offering support for the efficacy of the intervention. In addition, adolescents and mothers in the intervention group increased their PK after the intervention with mothers’ PK sustained over time.