The purpose of this study was to investigate a class-to-class online English-Portuguese "Teletandem" program that was conceived, negotiated, and implemented cross-collaboratively between the foreign language instructors and language resource center (LRC) staff at two large state universities--one in the United States and the other in Brazil. Ten English language students in Brazil were paired with 10 Portuguese language students in the U.S. for a 10-week Skype®-based tandem language exchange (TLE) project that was jointly delivered online across an international university partnership. A qualitative case study design was used to examine the attitudes, perceptions, views, and behaviors of the teachers, students, and LRC staff who participated in the project. The objective of the study was to shed light on the factors that facilitated and hindered Teletandem design, implementation and sustainability. Participant feedback was interpreted and contextualized by the researcher to provide rich descriptions of how Teletandem was optimized and how it impacted student learning. The findings suggest that Teletandem is an innovative, low-cost, high-impact language learning activity with vast pedagogical implications. As a lab supplement to traditional instruction, it enabled students at both sites to accelerate L2 development through authentic immersion and practice while making social connections with native speakers abroad. In addition, the results showed that--for many students--Teletandem heightened intercultural awareness, boosted confidence in the L2, and strengthened fluency skills while rendering a transformational learning experience. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]