This study aims at investigating key factors that determine competitive advantage in Tanzania using Structural Equation Modelling (SEM) method. The study uses cross-section survey design and non-probability sampling method; and data were collected from Dar es Salaam, Arusha and Tabora using a case study of textile and apparel industry. The sampling unit used were the employees of the industry knowledgeable on industry dynamics and with at least college education. The study proposes two inter-related micro and macro competitive advantage models. In the first place, exploration of the key underlying dimensions of both models was done using Exploratory Factor Analysis. Thereafter, based on the extracted principal components, SEM method using Confirmation Factor Analysis was used to find out whether the parameters of the micro model that involve Porter‘s Five Forces, Value Chain Management practices and Core Competencies; and macro model involving Porter‘s Diamond Model, produces significant CFA fit indices. The major findings are that, both the micro and the macro models are confirmed to be determinants of competitive advantage in Tanzania, as predicted by the theory. Furthermore, the results demonstrate linkage among the determinants. The diamond conditions, value chain management practices and core competency are indeed measures of competitive advantage. The determinants are considered to be key inputs for the strategic fit in the design of sustainable competitive advantage strategies for firms. Furthermore, the textile and apparel industry and government need to collaborate to improve diamond conditions to provide enabling environment necessary for competitive advantage. Lastly, with some adjustment, the model can also be replicated to other industries as well, in improving their competitive advantage