What is the prevalence of moral themes in textual corpora? Most previous moral mining research has been informed by Moral Foundations Theory (MFT). Here, we develop and evaluate an alternative moral mining tool based on the theory of Morality as Cooperation (MAC), using crowd-sourced annotations and the web-based hybrid content annotation platform, the Moral Narrative Analyzer (MoNA). We compare the empirical performance of the extended Morality as Cooperation Dictionary (eMACD) with previous dictionaries, including the extended Moral Foundations Dictionary (eMFD), across ten validation analyses, encompassing diverse corpora that include news media, journal entries, presidential speeches, social media, and movies. We find that eMACD outperforms previous dictionaries in most cases. We conclude that eMACD is an important addition to the methodological toolkit of researchers examining moral content in textual data, and we provide eMACDscore – a Python-based moral mining tool – to facilitate future research.