Reports or research investigations studying children in nature are rapidly expanding and increasingly diverse. This document reports a review of a particular part of this field-studies of constraints to recreation and participation in environmental and outdoor recreation programs. The findings result from a review of more than 125 journal articles, books, and reports that were published between 1980 and 2009. This report discusses how the current information concerning constraints to participation can be understood in terms of four concentrations or foci of work generated in this particular field of study. These foci, which are all well established in the literature, are (1) intrapersonal, interpersonal, and structural constraints, (2) significant life experiences, (3) environmental attitudes, values and beliefs, and (4) environmental behaviors. The recent research associated with each of these research areas is discussed in successive sections of the review.