A review of 25 technical assistance models and frameworks was conducted to identify the core elements of technical assistance practices. The focus of analysis was on generally agreed upon technical assistance practices that were considered essential for planning, implementing and evaluating the effectiveness of technical assistance. Results indicated that there are five major components of technical assistance and 25 different core elements. Analyses of the models and components found considerable variability within and between components in terms of the core elements that are considered most important or essential. Findings were used to define and describe the core elements of the technical assistance models and frameworks and how they can be used in research and evaluation studies to determine if the use of the core elements and practices are related to changes or improvements in program, organizational, or systems practices.