Snacking is a common dietary behaviour among adolescents contributing to more than one quarter of their total energy intake; however, the relationship between snacks and diet quality remains unclear. Hence, this study aimed to examine the characteristics of snacks among adolescents with different levels of diet quality. Dietary data collected from a nationally representative sample of Australian adolescents (12-18 years old, n = 935) using one 24-hour dietary recall in the National Nutrition and Physical Activity Survey were analysed. Snacks were defined based on participant-identified eating occasions, and diet quality was assessed using the Dietary Guideline Index for Children and Adolescents (DGI-CA). Marginal means and proportion of snack characteristics including snack frequency, snack energy density (ED), and commonly consumed foods at snack from the five food groups and discretionary foods at snack across DGI-CA tertiles (highest tertile indicating high guideline adherence) were estimated for both boys and girls using linear regression and logistic regression. Differences in means were tested using the F-test. The results showed no significant differences in the mean frequency of snacks across tertiles of DGI-CA scores. The mean ED of snacks decreased as DGI-CA scores increased in both boys (lowest tertile = 8.4, 95% CI [7.1, 10.0] kJ/g, highest tertile = 6.3 [5.4, 7.4] kJ/g) and girls (lowest tertile = 9.0 [7.8, 10.3] kJ/g, highest tertile = 5.9 [5.1, 6.9] kJ/g). As diet quality improved, the proportion of adolescents consuming discretionary (i.e., unhealthy) foods and foods from the five food group foods as snacks decreased and increased, respectively. In conclusion, adolescents with higher diet quality consumed snacks with a lower ED while lower proportion of them consume discretionary foods, and higher proportion of them consume from the five food groups. Encouraging the consumption of foods from the five food groups with lower ED as snacks presents an opportunity to enhance adolescent diet quality.