Most research examining individuals who follow different diets has combined vegetarians and vegans into a single group. To investigate whether this consolidation is justified, we analyzed possible differences between vegetarians and vegans for the Big Five personality traits in two studies. In our pre-study, we used data from a German convenience sample of 400 vegetarians and 749 vegans and found that vegans reported slightly higher scores in Openness compared to vegetarians (d = 0.22). In the preregistered main study, we used data provided by 1203 vegetarians and 128 vegans from the German Socio-Economic Panel Study; we found that vegetarians reported slightly higher scores in Neuroticism compared to vegans (d = 0.18) but did not differ in Openness. We found no differences in Conscientiousness, Extraversion, or Agreeableness in either study. Controlling for the socio-demographic variables of age, gender, and socio-economic status did not alter the pattern of results. Overall, these results suggest that there are no or only small differences in Openness or Neuroticism between vegetarians and vegans. Further studies utilizing very large, representative samples are needed to better understand the relationship between personality and diet groups.