This investigation analyzed the methods used over the past 35 years to study emotion regulation (ER) in children. Articles published from 1975 through 2010 were identified in 42 child clinical, developmental, and emotion psychology journals. Overall, 61.1% of published ER articles relied on one method and 23.6% used two methods. Analyses revealed (a) 82.8% of published ER research occurring within the past decade; (b) higher rates of observational methods with infant and toddler/preschool samples, but more use of self-report methodology with middle childhood and adolescent samples; (c) a longer history of published ER research with samples of infants to 5-year-olds, including the use of more longitudinal design, compared with older samples; and (d) a positive association between journal impact ratings and the use of physiological and observational measurement. Review of the measurement tools used to capture ER revealed great diversity in how emotion processes are understood and evaluated. (Contains 1 figure and 3 tables.)