This article reports on evaluation studies of the Virtual Tutee System (VTS) designed to enhance students' engagement in academic reading. The VTS is a web-based peer-tutoring environment in which students teach a virtual tutee about the content in course readings that students have been assigned to learn. With the VTS, students interact with virtual tutees by providing lecture notes and answering questions from these tutees. The initial prototype of the VTS was implemented and evaluated through two field trials in a college classroom. The purposes of the two field trials were to assess the efficacy of the VTS and improve its design. In the first field trial, students successfully completed the VTS and showed a deeper engagement in reading with the use of the VTS, but reported several design issues. Based on findings from the first trial, two modifications in the VTS design were made. In the second field trial, students used the revised VTS. They expressed enjoyment in teaching their virtual tutees and appreciated the value of the VTS. They also demonstrated a significant increase in their reading strategy use. The article concludes with design considerations for the VTS and implications for future research and development.