Parental educational involvement during middle school has received increased attention from researchers and policymakers because of its links to a variety of academic outcomes. Despite this increased attention, parental involvement has been inconsistently linked to academic outcomes among adolescents, indicating different types and levels of involvement that may be more beneficial for adolescents. Therefore, this study examined the nonlinear associations between parental involvement (home-based involvement and academic socialization) and academic motivation in an effort to better understand the nature of parental involvement in middle school. Using data from an ethnically diverse (57% Black/African American, 19% multiracial, 18% White/Caucasian, 5% Hispanic or Latino, and 1% Asian American) sample of 150 adolescents (56% female) in grades 6 through 8, findings showed no associations between home-based involvement and intrinsic or extrinsic motivation. There was, however, a significant nonlinear association between academic socialization and both types of motivation. More specifically, the positive association between academic socialization and intrinsic motivation was attenuated at high levels of academic socialization. There was no association between academic socialization and extrinsic motivation at low and moderate levels, but there was a positive association at high levels of academic socialization. These findings suggest that different types of involvement and greater amounts of parental involvement may not always benefit adolescents' academic motivation.