Recent work in moral psychology, claiming to show that human beings make moral judgments on the basis of multiple, divergent moral foundations, has been influential in both moral psychology and moral philosophy. Primarily, such work has been taken to undermine monistic moral theories, especially those pertaining to the prevention of harm. Here, I call into question one of the most prominent and influential empirical cases for moral pluralism, namely that of Jonathan Haidt and his colleagues. I argue that Haidt et al.'s argument is not as strong as it is often made out to be, given significant problems with the design of one of the key experiments used to ground the claim that there are divergent moral foundations across cultures. The flaws that I point out pose a significant challenge to Haidt et al.'s findings, and they have a detrimental impact on subsequent work based on this immensely influential experiment. Accordingly, I argue that both empirical and normative claims made on the basis of Haidt et al.'s findings should be treated with caution. I conclude by suggesting how some of these problems might be addressed.