Taxonomies play an important role in research in many fields including information systems. Since the publication of Nickerson et al. in 2013 numerous papers have been published in which taxonomies were developed using the method in this seminal paper. However, that method is limited to developing “flat” taxonomies while many taxonomies are “hierarchical”. The current paper provides formal definitions that distinguish between these types of taxonomies. It then introduces a preliminary method for hierarchical taxonomy development and demonstrates this method with an example. The paper concludes with unanswered questions that we are still exploring.