<p>Due to climate change, Vienna has experienced an increasing number of heatwaves during the past few decades, and the trend continues. While many adaptation strategies focus on technical innovations or lifestyle adjustments, these measures alone are insufficient to address the challenges posed by urban heat. Social capital, comprising bonding, bridging, and linking dimensions, is also an indispensable cornerstone of adaptation. This article investigates the role of different types of social capital in fostering adaptation to heatwaves, focusing on two highly heat-vulnerable areas in Vienna. Semistructured interviews and participatory workshops with heat-vulnerable residents were conducted to explore how social capital influences adaptation to heatwaves within these sociospatial contexts. The findings highlight the importance of bonding and bridging social capital in fostering mutual help and knowledge sharing at the neighborhood level during heatwaves. Different potential measures and their influences on the development of bonding and bridging networks are discussed. Linking social capital can also facilitate adaptation but could be enhanced through improved communication between the city administration and heat-vulnerable groups as well as greater accessibility of municipal services related to heat. Civic participation processes and community-oriented initiatives in climate change contexts can also strengthen different types of social capital. The article concludes that social capital is a vital resource for effective adaptation to heatwaves in Vienna and comparable large cities in Central Europe.</p>