Abstract In this paper, we study how phonotactic constraints can play a role in contact-induced morphological simplification. We hypothesize that, in languages with constraints on certain consonant sequences, L2 speakers acquiring the language overgeneralize these constraints and avoid consonant sequences formed by morphological affixing. The resulting process of reduction of such sequences could then lead to loss of morphological affixes. We evaluate this hypothesis using data from Alorese, an Austronesian language spoken in eastern Indonesia, which underwent morphological simplification and has a large proportion of L2 speakers. Results from an agent-based model, which allows for mechanisms to be tested in isolation, indicate that phonotactic mechanisms indeed play a role in contact-induced morphological simplification. Phonotactic mechanisms lead to the strongest simplification when combined with a generalization mechanism, which spreads the simplified forms across different verbs. The model results underline the role of multiple interacting mechanisms in language change.