This paper is aimed at discussing the concept of public service co-production, adopting a critical perspective. Even though the involvement of users in planning, designing, and delivering public services dates back to more than 30 years ago, the literature on public service co-production is still not consistent. From this point of view, a literature review was performed, with the eventual purpose of contextualizing the findings suggested by the literature about the attributes and the effects of public service co-production. To collect the relevant scientific literature, two citation databases were queried. The joint use of symmetric research criteria paved the way for the collection of 165 records. All of them were screened in their titles and abstracts to remove redundancies and non-relevant items. 61 records were included in the systematic review and informed the findings of this study. Public service co-production is understood as a critical approach to achieve enhanced sustainability in the public sector; however, co-production could produce several side effects, including equity issues and discrimination in the access to public services.