Research Findings: The purpose of this study was to investigate how neighborhoods and neighborhood socioeconomic disadvantage impact school readiness over time. School readiness was measured using the Early Development Instrument (EDI) for 3 populations of kindergartners in 2001, 2003, and 2005 in Saskatoon, Saskatchewan, Canada. EDI results revealed that mean scores for the EDI domains of (a) physical health and well-being and (b) communication and general knowledge have been decreasing over time, although this varied according to neighborhood. A derived summary measure of socioeconomic disadvantage at the neighborhood level was significantly associated with declining scores in the EDI domain of physical health and well-being. Practice or Policy: These findings suggest a need for policy and programs that address the underlying determinants of poor school readiness scores, such as socioeconomic disadvantage at the neighborhood level. (Contains 8 tables, 4 footnotes, and 4 figures.)