Measurement invariance across time and reporter is rarely reported in the literature for measures of youth disclosure, even though it is often necessary to establish at least strong invariance before proceeding to further analyses such as comparing means across time or reporter. Measurement invariance was examined across time (ages 11, 14, and 17) and across reporter (youth report of disclosure to mother, youth report of disclosure to father, mother report of youth disclosure, father report of youth disclosure) with a sample of 348 youth and their parents. Youth report of disclosure to mothers demonstrated strong invariance across ages 11-14 and 14-17, but strong equivalence was not found for mother report over time across any age. Youth report of disclosure to mothers and fathers demonstrated strong equivalence at ages 11, 14, 17, and across ages 11-14-17. Mother and father reports also demonstrated strong equivalence at ages 11, 14, and 17. The item "I talk with my parent about how I am doing with school work" had lower factor loadings and higher intercepts at age 11 than at other ages for fathers and mothers and compared to youth report. Implications for youth disclosure theory and construct development are discussed.