This paper aims to analyze the development of the rule of law and its key characteristics as a principle within public governance model (PGM) research. In the study, we analyzed two main EU cultural and geographical subgroups, selected old and new EU member states, in order to identify the main convergences and differences characteristic of the respective clusters. With the accession to the European Union, these acceding countries were to transfer EU law into national law and reform their governance models accordingly. The aim of the research was achieved by following an original methodology, encompassing 431 relevant scientific papers from the Scopus database. Th e known QDA Miner 5.0.11 soft ware package was selected as the main tool for the analysis. Th e research questions were aimed at covering: (i) the role of the rule of law as one of the key governance principles in relation to the countries’ historical legacy and different governance models, (ii) the relationship between the rule of law and other governance principles and (iii) opportunities for further research within the two selected geographical subgroups. The results, concerning the first research question, reveal a greater frequency of papers per year about the relevant PGM studies focusing on the old EU member states. Likely, due to a broader socio-administrative tradition within these countries, law-related topics are better covered. As regards the relationship between the rule of law and other governance principles, we have shown that the rule of law as a principle is importantly related to effective governance and PA reforms and must not be taken as an antipode to efficiency. In new EU MS, i.e. Central and East Europe (CEE), in particular the rule of law in administrative relations is also one of the salient elements of the on-going transitional development compared to the old Western democracies. However, within the processes of privatization, globalization and marketization, the rule of law is challenged; even with PAR that might undermine the core principles of democratic governance. While demanding further research, encompassing specific socio-economic needs of individual public administrations and an evaluation of legal and related highly important reform preconditions proves vital for tomorrow’s public administration, more effectively and efficiently coping with the needs of the modern society.