Background: The replacement of refined grains in the diet with whole grains may help prevent chronic disease and excess weight gain, but intakes in adolescents are often lower than recommended. Objectives: This study aimed to examine demographic disparities and 5-y longitudinal and secular trends (1999-2004) in whole-grain intake among 2 cohorts of Minnesota adolescents. Design: Whole-grain intake was examined among 996 adolescent males and 1222 adolescent females who were Project EAT (Eating Among Teens) participants in 1999 and 2004. Multinomial logistic regression models were used to examine demographic differences in whole-grain intake. Mixed linear regression models were used to estimate 1) longitudinal trends among 2 cohorts of adolescents during developmental transitions and 2) age-matched secular trends between the cohorts at middle adolescence. Results: In 1999, 11% of adolescent males and 13% of adolescent females reported that they consumed more than one daily serving of whole grains. Whole-grain intake was lowest among youth of the Native American and white races and among youth of high socioeconomic status. During the transition from middle to late adolescence, whole-grain intake increased by a mean of 0.14 daily servings among adolescent males and 0.09 daily servings among adolescent females. No significant changes in whole-grain intake were shown among either sex during the transition from early to middle adolescence. Yeast breads, popcorn, and ready-to-eat breakfast cereals were major sources of whole grains in 1999 and 2004. Conclusion: Findings suggest the need to advance efforts that target improvements in the amount of whole-grain foods selected by adolescents.