This article addresses pragmatic issues regarding the assessment of puberty in research on adolescent health and development. Because pubertal processes have a major effect on physical, psychological, and social development, we posit that the assessment of pubertal status is at least as important as the specification of age for characterizing adolescent participants in research studies. Yet, a sampling of recent literature shows that the majority of publications addressing health and developmental issues in adolescence lack any measure of puberty. A more comprehensive review of 447 articles reporting to have assessed puberty reveals considerable inconsistencies in methods, definitions, and conceptualizations of puberty and its stages, which highlights the need for better standardization. This article provides an in-depth review of existing methods to assess pubertal status and timing and enumerates the relative merits and shortcomings of several approaches. Conceptual and practical guidelines are provided for selecting specific measures to assess puberty with an emphasis placed on the need for these choices to be driven by the specific goals of the research. (Contains 2 tables and 3 figures.)