Mechanically stabilized earth (MSE) retaining walls have steadily grown in popularity due to their low cost, ease of construction, and excellent performance record. Observations from post-earthquake reconnaissance efforts have also indicated that these retaining wall systems exhibit excellent performance under seismic loading, often exceeding the performance of conventional rigid and semi-rigid walls. However, significant questions remain with regard to seismic design procedures for MSE walls, due in part to lack of sufficient test data under dynamic loading. The objective of this paper is to describe a new research program at the University of California-San Diego (UCSD) to conduct dynamic tests of large-scale (5 to 7 m tall) MSE retaining walls using a large outdoor shake table. The advantage of this approach is that test specimens can be constructed using realistic materials and methods, and yet still be shaken to accelerations approaching 0.7g. The research program is expected to provide benchmark data that researchers can use to develop improved design methods for MSE walls and to refine numerical models for assessment of their seismic performance.