A world becoming more digitally transformed and connected poses significant challenges for IT organizations, requiring increased attention to the usability of their software products and, consequently, to the systematic establishment of usability engineering (UE) processes. Typically, the establishment of software processes is guided by software process capability/maturity models (SPCMMs), such as CMMI or ISO/IEC 15504. However, it seems that these commonly adopted models do not explicitly cover usability engineering (UE) processes. Thus, a question that arises is, if there exist process capability/maturity models focusing explicitly on usability engineering? If yes, to which degree do they assist in the assessment process? To answer this, we conducted a systematic literature review on usability capability/maturity models (UCMMs). A total of 15 UCMMs were identified and analyzed, synthesizing information on their measurement framework and process reference model, usage support and how they have been developed/validated. We observed that most of the models are based on consolidated SPCMMs, such as CMMI or ISO/IEC 15504. Only few UCMMs customized for specific contexts were found. Although all UCMMs propose or reference a measurement framework, only 5 UCMMs define a proper process reference model. Most of the models also do not offer support for their usage, which may hinder their larger scale adoption in practice. Furthermore, we noted a lack of information on how most of the models have been developed and validated, which leaves their validity questionable. These results indicate the need for further research on UCMMs taking into consideration the increased importance of usability in software product quality. (C) 2017 Elsevier B.V. All rights reserved.