Remote Laboratories (RLs) break barriers in education since they provide real experimentation anytime and anywhere. However, their greatest drawback is the lack of immersion. However, Extended Reality (XR) can overcome this shortcoming through the integration of AR, or VR techniques, into remote experimentation, thus developing Extended Reality Remote Laboratories (XRLs), which can be Augmented Reality Remote Laboratories (ARLs), or Virtual Reality Remote Laboratories (VRLs). Our study consists in a systematic review concerning the state-of-the-art of XRLs during the period 2000-2022. Findings from the systematic review generated two main results. First, a thorough analysis that reports: a timeline of publications, studies per country, most influential universities, most popular journals and conferences, most cited publications, description of ARLs, description of VRLs, and most notable publications. Secondly, a classification of the XRLs encountered during research, and a proposed architecture for creating XRLs, in order to guide developers wishing to integrate XR into their experiments.