The present study aims to explore the cognitive processes of older students during their peer tutoring support of freshmen engaged in asynchronous discussion groups. Stimulated-recall was applied to study the underlying motives for specific tutor behavior in the online discussions and to make tutors' concerns explicit. A grounded theory approach was used to analyze the interview transcripts. A constant comparative analysis of the data resulted in six issues associated with peer tutors' cognitive processing in relation to actual tutoring behavior: strategy use, reasons for intervention, experience with online discussions, evaluation of faculty support, satisfaction with tutor-tutee interaction, and evolution over time.Furthermore, the results point at tutor worries. A major dilemma concerns the persistent problem of deciding when, how exactly, and how frequently to intervene. A second tutor dilemma is associated with the multidimensional tutor role. Thirdly, peer tutors struggle with the fact they are not professionals so not expert in the learning materials.2 Introduction An extensive body of peer tutoring studies documents the impact of introducing peer tutoring programs within a face-to-face context (see e.g., Carroll, 1996;Duran & Monereo, 2005;Topping, 1996;Webb, 1992). However, apart from the recent work of McLuckie and Topping (2004) and De Smet, Van Keer, and Valcke (2008), research into online peer tutoring is relatively scarce. Moreover, in the limited number of studies available, the thought processes underlying the tutor"s online facilitation approaches in the actual management of younger peers" learning processes is rarely addressed. The present study aims to fill this research gap by focusing on the thoughts and reflections of older students during their online peer tutoring support of freshmen. This purpose may assist in controlling the commitment and responsibility on the older peers in the tutoring experience. As it is not common to analyze thought processes by means of a survey or building on questionnaires, qualitative interpretative research is chosen. In line with the work of Bennett and Marsh (2002) on training programs for online tutors, fourth-year university students, who participated in the present study as cross-age tutors, are engaged in stimulated-recall to reflect on their online tutor role. Additionally, this technique is most useful for generating research-based understanding of peer tutors" thoughts on their field experiences. Moreover, the information obtained from the interviews can identify elements valuable for the design of future tutor training programs.