The U.S. government relies heavily on security cooperation and security assistance programs to build partner-nation capacity as a means of furthering U.S. national security interests. Special Operations Forces (SOF) have contributed to this effort, particularly in the training and advising of foreign forces. However, the overall alignment of these efforts can sometimes be problematic. Furthermore, in a fiscally austere environment, planners will be forced to make difficult decisions about which countries will yield the best results when SOF are employed to build capacity. This book uses two RAND reports "What Works Best When Building Partner Capacity and The RAND Security Cooperation Prioritization and Propensity Matching Tool, published in 2014, to assess which factors are most critical for SOF efforts to build partnership capacity. It then relates these factors to countries where SOF training and advising might be employed. It finds that the countries best suited to SOF training and advising are the ones that the RAND reports suggest are the least likely to build capacity. Given this insight, this thesis recommends that Theater Special Operations Commands continue to explore new and creative solutions for security cooperation programs while working with interagency actors and industry to build partnership capacity.