Abstract In second language (L2) research, aptitude is typically viewed as a multicomponential, cognitive construct. Yet we know that L2 learning is influenced by multiple learner individual differences (IDs) besides cognitive abilities and that these IDs interact. In this article, we consider the affordances and implications of working toward a broader theory of language aptitude. Inspired by the theory of aptitude complexes, we examine the joint functioning of cognitive, affective, conative, and contextual processes in L2 learning. We conducted a large, exploratory study of aptitude with 544 learners of L2 Dutch. We used exploratory graph analysis to estimate a partial correlation network of 25 variables, combined with a community detection algorithm to identify communities of closely related variables. Results showed five communities of aptitude variables: cognitive abilities, proficiency and use, motivation and effort, self‐beliefs and emotion, and pro‐social behaviors. Learners with higher levels of multilingualism and less external pressure to learn Dutch made more L2 gains. Results also showed that L2 use and attitudes toward the Dutch community had an effect on L2 gains, via proficiency level and length of residence. Our findings fit with the theoretical framework and highlight the importance of working toward a multivariate, integrative theory of language aptitude.