This study is aimed at presenting a critical overview of recent research studies on the use of educational online games as collaborative learning environments in Tertiary Education (TE), namely higher education and vocational training, with a view to identifying: a) the elements that online games should include in order to support fruitful and sustainable constructivist and collaborative learning experiences within TE institutions; b) the impact of online games on students' motivation, academic performance and collaborative practices; c) the impact of the use of online games for educational purposes on faculty workload, teaching and assessment practices, and management of classroom dynamics; and d) the challenges that TE institutions face when new, very learner-centered, but also potentially addictive and distractive, learning modes, such as learning through online games, are introduced into the various curricula. The study also examines certain practical and technical issues related to the use of online games in TE, such as the costs of the software needed and the adequacy of the computer and networking infrastructures. (Contains 2 figures and 2 tables.)