This article explores how cross-sector partnerships (CSPs) operating in a development context built resilience during the outbreak of the COVID-19 pandemic. Based on a qualitative analysis of eight partnerships operating in East-Africa, Central America, and Indonesia, I show how CSPs engaged in three practices of resilience building (i.e., forming unconventional alliances, mobilizing digital technologies, and building subnetworks), which allowed them to remain functional despite facing adversity. In addition to fostering their resilience, my findings show how engaging in these practices enabled (...) the CSPs to develop new capabilities (i.e., improved abilities to engage with beneficiaries) that benefit them in the long run. Based on these insights, I advance our understanding of resilience building by unpacking this concept on a CSP level. Furthermore, by unfolding the relevance of incidental learning in a cross-sectoral setting, I widen our knowledge of learning processes in CSPs. (shrink)