Firms use platform strategies to offer a broad portfolio of products. Development of platforms has become dispersed across locations and partner firms as technological platforms enable co-creation of value in the platform ecosystems by complementors. In this paper, we look at the entry mode choices for platform firms when expanding abroad. We study the relationship between modular architectures and determinants of choices for selection of complementors. The link between architectural modularity and this decision is important as this enables us to examine questions related to success of task partitioning at an industry level. Our findings suggest that besides modularity, factors such as access to specialist expertise, availability of complementary skills and experience of the complementors in a varied range of technologies and systems play a significant role in the the entry mode choice