In recent years, firms have become increasingly involved in sociopolitical issues via corporate political advocacy (CPA) and corporate social responsibility (CSR) while consumers have become more politically polarized and skeptical of political institutions. Merging these developments, the present work examined similarities and differences in response to CPA and CSR, and the implications for consumer polarization and radicalization. Utilizing three studies across numerous domains, we demonstrate that: (a) CPA (CSR) results in increased negative (positive) sentiment on social media, (b) relative to CSR, CPA results in more negative and polarized reactions due to the controversial nature of CPA, and (c) polarized responses to CPA are stronger among consumers lower in political efficacy. Together, the present findings shed light on the distinction between CPA and CSR and illustrate how (and among whom) CPA may contribute to polarization and radicalization via negative sentiment expressed through social media and consumer actions. Theoretical contributions, practical implications, and future research directions are detailed.