Identity has important implications for consumers’ choices in the marketplace. While prior research has mainly studied identity at the individual level, consumers’ social identities are growing more relevant in the marketplace. This dissertation examines how these social identities affect socially responsible decision-making. Using experiments as my primary method, I study how consumers’ political and couple identities can affect their decision-making in the context of sustainable consumption practices, COVID-19 behaviors, and the sharing economy. Across 16 online experiments, two Facebook split tests, and one field study, this dissertation demonstrates the critical implications of political and couple identity in the socially responsible decision-making process. 

First, this dissertation shows that consumers’ political identities influence their willingness to engage in sustainable consumption, COVID-19 prevention behaviors, and support for peer-to-peer providers in the sharing economy. Second, this dissertation examines sustainable consumption in a romantic relationship context and demonstrates that consumers’ sustainability-related decisions can influence their partners’ sustainable choices, highlighting the importance of couple identity. Overall, this dissertation contributes to the literature on identity and socially responsible decision-making and provides practical implications for marketers and policymakers who aim to improve consumers’ socially responsible behaviors in the marketplace.