The sysmtematics of cervids has intrigued researchers for over 150 years. The first approaches were based on the morphology and comparative anatomy of cranial (skull) and postcranial (skeleton) material. The initial gross classification, particularly the split of Cervidae into two subfamilies, Cervinae and Capreolinae, still holds today. With the development of molecular methods, a new level of investigating systematic relationships of cervids was reached. Phylogenetic reconstructions based on molecular data are partly congruent with the classifications based on morphology; however, there are some conflicts across different data types. In the last two decades, molecular and morphological data were used in combined approaches, which further documented robust and conflicting splits in the phylogeny of cervids. There is consensus concerning the higher hierarchical classification; Cervinae consists of the tribes Muntiacini and Cervini and the systematic relationships within these two clades are—with a few exceptions—resolved. Capreolinae consists of the tribes Alceini, Capreolini, Odocoileini, and Rangiferini. The systematic relationships within Capreolinae are more controversial. The position of Capreolini and Alceini is uncertain, and there are many polyphyletic taxa within Odocoileini, which are currently under taxonomic revision. The most recent comprehensive studies were able to support and confirm some of the previous hypotheses while also documenting and highlighting controversies within the phylogeny and systematics of cervids.