For three decades, motivation researchers have used the construct of engagement as a holistic lens for understanding how children interact with learning activities, highlighting that each child has a unique engagement profile comprised of behavioral, emotional/affective, cognitive, and social dimensions. As researchers continue to piece together the multifaceted nature of engagement, a pressing need has emerged for a synthetic, coherent review of the extant literature on engagement that clarifies its conceptualization, identifies its key facilitators and consequences, and delineates its functions. Using a developmental-contextual approach, this chapter presents an integrative theoretical perspective on engagement, emphasizing that engagement is the product of dynamic developmental and relational processes involving transactions across multiple ecologies. The integrative model of engagement offers a nuanced and comprehensive perspective on the multiple pathways—psychological, cognitive, and sociocultural—underlying the development of youth's engagement. The conceptualization and study of engagement as a multidimensional construct produced by an ongoing interaction between the individual and the environment informs the identification of the particular personal, contextual, and sociocultural factors that foster or undermine engagement, while increasing understanding of the psychosocial mechanisms through which the learning environment influences engagement.