Cross-cultural research involves explanatory arguments framed at the meta-level of a cohort of societies, each with its own historical development as an internally structured and organized system. Historically, cross-cultural research on hunter-gatherer groups initially was in accord with the general anthropological interest in determining the ideational basis for differences in systems of social organization, but more recent work has shifted emphasis to the phenomenal level of factors affecting the mode of adaptation to an external environment. This has left a major lacuna in our understanding of the reasons for crosscultural differences among ideational systems such as kinship terminologies in huntergatherer societies. I address this lacuna in this article through cross-cultural comparison of hunter-gatherer kinship terminologies at an ideational, qualitative level. The means for so doing is first worked out using the kinship terminology of the Hadza, an East African hunter-gather group. Next, comparison of the Hadza and their kinship terminology with two other hunter-gatherer groups prominent in the anthropological literature, along with their kinship terminologies, makes evident a major disjunction between, on the one hand, the similarity of hunter-gatherer societies at the phenomenal level of activities such as food procurement and, on the other hand, striking differences among the same groups at the ideational level of the structural organization of their kinship terminologies. The reason for the striking differences between the ideational and the phenomenal levels is not immediately evident and remains a topic to be addressed in future cross-cultural research.