Meningkatnya tren gaya hidup sehat dan penetrasi smartphone membuka peluang bagi pengembang aplikasi untuk menciptakan aplikasi sport and fitness tracker yang dapat memantau aktifitas fisik pengguna bersamaan dengan data lainnya. Penyedia layanan perlu mengetahui faktor-faktor yang memengaruhi keputusan pengguna dalam menggunakan aplikasi sport and fitness tracker, salah satunya dengan pendekatan extended technology model. Penelitian ini menggunakan pendekatan extended technology acceptance model yang dikombinasikan dengan innovation diffusion theory. Penelitian ini melibatkan 216 responden dan dianalisis menggunakan pemodelan Partial Least Square-Structural Equation Modeling (PLS-SEM). Hasil penelitian ini menunjukkan bahwa perceived usefulness dan perceived ease of use berpengaruh terhadap intensi penggunaan aplikasi sport and fitness tracker. Selain itu, variabel compatibility juga berpengaruh terhadap perceived usefulness dan variabel trialability dan visibility berpengaruh terhadap perceived ease of useThe increasing level of healthy lifestyle along with the high penetration of smartphone creates a big opportunity for application providers to establish sport and fitness tracker app. This application has the ability to monitor the user physical activities along with the other data. Providers need to understand the factors which are considered to affect the decision to adopt this technology. The proposed model is extended technology acceptance model and inovation diffusion theory. This study consist 216 respondents and was analyzed using Partial Least Square-Structural Equation Modeling (PLS-SEM. The results suggest that perceived usefulness and perceived ease of use positively affect the intention to use sport and fitness tracker app. This study found compatibility positively affect perceived usefulness also trialability and visibility affect perceived ease of use as well.