Purpose: This paper aims to look at the characteristics of internal quality assurance (IQA) systems of higher education institutions to understand whether these systems tend to reproduce a given model, externally defined and suggested to institutions, or rather to be shaped by institutions' features and interests. Design/methodology/approach: The study is supported in the analysis of the content of self-assessment reports of 12 internal QA systems certified, in Portugal, between 2012 and 2015. An analysis grid was used based on three categories: IQA systems' historical framework, structural/managerial component and monitoring, assessment and continuous improvement. Findings: Institutions tended to follow a "one size fits all" approach, meaning that external (European and national) quality assurance (QA) references were used in an identical way, giving origin to rather similar IQA systems. Institutional characteristics do not seem to have played a relevant role, eventually due to institutions' will to obtain their systems' certification and, thus, achieve a light-touch external QA. Research limitations/implications: The study was based on the analysis of only certified IQA systems and relies on document analysis. It would be interesting to also include non-certified systems, in a comparative perspective, complemented with data deriving from interviews and/or questionnaires with some of the actors involved in the certification process. Practical implications: The study provides an understanding of how IQA systems are being implemented in Portugal. Thus, it can be of interest to other institutions as well as to QA agencies. Originality/value: The study addresses a topic still relatively absent from research on QA in higher education, being of interest for researchers in the field.