Research on achievement goals is voluminous but focused primarily on intrapersonal regulation. In the present article, we emphasize the integral role that achievement goals also play in the broader process of interpersonal judgment. We establish a new interpersonal approach to achievement goals that integrates the extensive achievement goal literature with the well-established social relations model (SRM). We introduce and formally define the interpersonal concept of achievement goal perception, present a formal methodological approach to studying this novel concept using a Bayesian implementation of the multivariate SRM (MSRM), and put the proposed integrative approach to the test with an in-depth empirical study that directly addresses fundamental questions of achievement goal perception. In this empirical study, we measured four types of achievement goal perceptions-mastery-approach (MAP), mastery-avoidance (MAV), performance-approach (PAP), performance-avoidance (PAV)-across 1,809 student-classmate dyads from 42 small discussion-based undergraduate classes. Results indicated a predominantly perceiverdriven process consisting of self-other agreement for MAP, MAV, and PAV goals but not PAP goals, assumed similarity for each achievement goal, and greater assumed similarity among closer classmates. Achievement goal perception provided incremental predictive utility for two gold-standard educational outcomes-academic performance and intrinsic motivation-among both perceivers and targets, and four additional educationally relevant constructs-perceived class value, perceived effort investment, perceived competence, and peer help-seeking-among perceivers. Having laid the theoretical, methodological, and empirical foundations, we discuss this new interpersonal approach to achievement goals alongside contemporary research on achievement motivation and interpersonal judgment.