PurposeThe purpose of this experimental study is to examine the effects of climate change corporate social responsibility (CSR) and corporate social advocacy (CSA) messages on public perceptions of companies and collective action intentions.Design/methodology/approachThis study employs a 2 (message type: CSA vs CSR) × 2 (environmental issue: single-use plastics vs renewable energy) × 2 (company: Target vs Walmart) plus control online experimental design.FindingsThere were no main effects of message type on outcomes; however, green consumer identity moderated the relationship between message type and green purchase intention as well as negative word-of-mouth.Originality/valueThis study responds to calls by scholars to empirically compare the effects of CSR and CSA messages. Additionally, we consider group-level processes, like ingroup identity, in influencing strategic communication outcomes.