Research indicates that cannabis continues to be a popular illegal drug internationally. Furthermore, adolescent rates of use appear to be significant. Whilst the non-acute effect of cannabis use on adult cognition has been extensively researched, there has been less examination of adolescents. This study aimed to investigate the non-acute relationship between cannabis and cognitive function in a sample of adolescents with a continuum of cannabis use, taking into account additional predictor variables (psychiatric functioning, general functioning, demographics and other drug use). Seventy adolescents were recruited from clinical and community sources as well as through newspaper advertisements. After 12 hours abstinence from cannabis, adolescents completed a two-hour interview covering: demographics; alcohol and drug use history; drug use in the past 28 days; depression; further psychiatric functioning (including ADHD and Conduct Disorder); and cognitive functioning as measured by computerised tasks (CANTAB) and traditional pen and paper tests. Adolescents who were regular cannabis users (more than once a week) had a significantly poorer performance on four measures of cognitive function reflecting attention, spatial working memory and learning. Cannabis use remained an independent predictor of performance on the working memory and strategy measures after additional predictor variables were included in a multivariate regression analysis. The results suggest that aspects of adolescent cognitive function are independently related to the frequency of cannabis use beyond acute intoxication.