The present study seeks to investigate the effects of technology spillover on the performance of automobile companies. One of the most important indicators in evaluation for cars manufacturing companies’ performance is sales; hence, this study focused on sales variable and got it as a representative of Technology spillover. To this aim, the sales data collected from the domestic car manufacturing companies. For this mean sales pattern during ten years is recognized using Seasonal ARIMA (S-ARIMA) model. Akaike Information Criterion (AIC) and Schwarz Bayesian Information Criterion(BIC) used to select the most appropriate model. It is found that the selected model can be applied to forecast the sales with Mean Absolute Percentage Error (MAPE) in the range of 6%. This research also confirmed the idea, if Foreign Direct Investment (FDI) is taking place in developing countries, with regards to the necessary conditions and infrastructures, technology spillover occurs, and meaningful changes in factory performance would happen. Also, proposed forecasting model can help senior managers of domestic companies in mid-term and long-term planning.