Smart home (SH) products and services aim to enhance the comfort, convenience, security, entertainment, health, education and communication of tenants and their guests enabled by information technology platforms. Despite ongoing waves of enthusiasm, the SH market has remained a niche for more than three decades. At the same time, recent forecast expect the market to grow at high rates in the upcoming years as various global players, like Google, Apple, AT&T, Cisco and Samsung, are lining up with own SH platform initiatives. Accounting for the multi-sidedness of the market, we employ a platform ecosystem perspective to investigate the role of complementary assets for SH adoption by consumers and firms. Based on interviews with 25 experts from 22 companies, our qualitative content analysis reveals and prioritizes complementary goods, sales channels, brand image, expertise, support infrastructure, operational footprint and financial resources as critical complementary assets. Further, we provide managerial implications for platform sponsors regarding the affiliation with complementary suppliers, the legitimacy of sponsorship, platform openness as well as on platform envelopment.