Both adolescent and parent psychiatric symptoms are well-established risk factors for adolescent substance use (SU), but the ways that these symptoms interact are not well understood. This study examined the interactive effects of parent and adolescent psychiatric symptoms on adolescent frequency of alcohol and marijuana use, over and above the effects of parental SU. Seventy adolescents presenting to a community mental health center (CMHC) participated. Parent and adolescent psychiatric symptoms were measured with the brief symptom inventory (BSI) and child behavior checklist (CBCL), respectively. Hierarchical regressions revealed different patterns for adolescent alcohol and marijuana use. For alcohol, the BSI parent phobic anxiety subscale predicted increased adolescent use while the parent interpersonal sensitivity subscale predicted decreased use: the effects of these parental symptoms were strongest among adolescents with higher levels of externalizing problems on the CBCL. For marijuana, the BSI parent psychoticism subscale predicted increased adolescent use, whereas paranoid ideation predicted decreased use. Results suggest that adolescent SU treatment and assessment should attend to both adolescent and parent psychiatric symptoms.