Although there are tools to assess student's readiness in an "online learning context," little is known about the "psychometric" properties of the tools used or not. A systematic review of 5107 published and unpublished papers identified in a literature search on student online readiness assessment tools between 1990 and 2010 was conducted. The objective of this paper was to identify via a systematic review different tools allowing to assess the level of student's preparation in an online learning environment and which were published or not in scientific journals, and determine which of these tools have been validated. The results of the systematic review show that a standard tool does not exist, and that only ten instruments have been developed and published over the past 20 years to assess student's readiness. In addition, few tools published demonstrated good psychometric qualities, and many unpublished tools, considered as homemade tools, were internally developed in the universities by a team of professors without regard to their psychometric quality. Also, it appears that the tools that were published in scientific journals are rarely used by universities that offer online courses. Generally, the universities prefer to develop their own instrument that fits their online programs.