The multidimensional personality questionnaire-brief form (MPQ-BF) (Patrick, Curtin, & Tellegen, 2002; Tellegen, 1982) was administered to a sample of adolescents ranging from 13 to 17 years of age and a sample of young adults ranging from 19 to 23 years of age. The MPQ-BF is believed to provide a richer understanding of key personality traits and dimensions but is less widely used; particularly with the current two age groups. Significant differences were found between the adolescents and the young adults in the overall dimensions of constraint and positive emotionality. An age by gender interaction was found in the overall dimension of negative emotionality. These differences are discussed in terms of both developmental and neurological changes that take place over this age span.