To date, no studies have documented how much early childhood experiences have changed over time. In the current study, researchers use two large, nationally representative datasets of kindergarten entrants to document the following: (1) How have children's early childhood experiences changed between 1998 and 2010?; (2) To what extent have socioeconomic "gaps" in children's early experiences changed over time?; and (3) Did differential changes in early childhood experiences across sub-groups lead to a narrowing of achievement gaps? This study investigates changes along a diverse set of measures to try to capture wide-ranging measures of early life experiences. These include exposure to preschool, active parental engagement (e.g. joint child-parent activities and outings), home resources (e.g. books in the home, access to a computer), and parenting approaches (e.g. use of disciplinary practices) among others. After carefully documenting the trends over time, the authors explore the extent to which these changes are associated with narrowing achievement gaps in literacy and math. Tables are appended. [SREE documents are structured abstracts of SREE conference symposium, panel, and paper or poster submissions.]