The interaction approach to second language acquisition (SLA) suggests that changes that occur during conversation facilitate second language development by providing learners with opportunities to receive modified comprehensible input and interactional feedback, to produce output, and to notice gaps between their interlanguage and the target language through negotiation for meaning (Gass & Mackey, 2007; Long, 1996). Numerous empirical studies and meta-analyses have demonstrated positive effects for interaction (e.g Keck et al., 2006; Mackey & Goo, 2007). However, despite an increasing body of evidence examining synchronous computer-mediated communication (SCMC) from an interactionist perspective (e.g. Blake, 2000; Smith, 2004; Yilmaz, 2012), the efficacy of interaction in computer-mediated contexts has been less clear so far. The current study reports on a synthesis and meta-analysis on the relative effectiveness of interaction in SCMC and face-to-face (FTF) contexts. The primary studies included in the analysis were journal articles or dissertations published between 1990 and 2012, retrieved through searches in CALL and applied linguistics journals and texts. Results demonstrate that interaction in both SCMC and FTF had positive impacts on L2 development, with comparative findings revealing a small, although non-significant, effect for interaction in SCMC on measures of L2 learning outcomes. When the development of learners' productive and receptive skills were the focus, results showed a small effect for SCMC on learners' productive skills and a small effect for FTF on learners' receptive skills. Additionally, analyses investigated learners' written and oral skills, this time with results indicating a small effect for interaction in SCMC on written skills and a small effect for FTF interaction on oral skills. In sum, these results reveal several promising trends regarding interaction in SCMC. Furthermore, there were no significant differences between the two modes, suggesting, importantly, that in this meta-analysis the mode of communication has no significant impact on the positive developmental benefits associated with interaction. This research also found a number of issues regarding methodological quality, including inconsistent reporting of statistical tests and procedures. Finally, areas are identified within SCMC interaction research that are ripe for further investigation and suggestions are made for methodological improvements and directions for future research. [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.]