This study investigated critical thinking indicators of students' postings on the asynchronous online discussion forums on the learning management system (LMS) at Arab Open University (AOU), Jordan. The models used to diagnose nineteen students' postings were Garrisons' (2001) thinking skills and Newman (1995). Results revealed that participants' postings reflected the critical thinking indicators proposed by Newman like relevance and importance, but students need to enhance skills like justification, and critical assessment. According to Garrisons' model, participants could identify, and explore problems, but they need support to evaluate the problem and integrate solutions into their existing knowledge. The findings reveal that participants acquire essential critical thinking skills, but they need to focus on higher order skills. Further research should be conducted using different courses issues to impart the critical thinking indicators that students need in higher institutions. In addition, instructors should be trained on how to formulate online tasks that stimulate high level of thinking.