Municipal solid waste (MSW) generation is a complex function of socio-economic characteristics, climatic factors, and public policies and strategies. This study develops a model based on the multivariate econometric approach that considers these parameters to forecast and manage the MSW. The model applies statistical tools to select suitable function and most relevant explanatory variables that have strong relationship with solid waste generation. The model applicability is demonstrated with an example of MSW generation in Mashhad, Iran. The results indicate that the number of employees, population, household income, and temperature are significant variables of MSW generation in Mashhad. Socio-economic variables have been evaluated so far, but the impact of climatic factors is not considerably assessed in the previous studies. Thus, in this study, for the first time, the impact of temperature as a significant variable on MSW generation is assessed. The developed model can be used for forecasting the values of disposal waste in the study area. Therefore, by determining the quantity of the disposal waste, decision making for the investment required for machinery, transition stations, disposal capacity, and the required field for sanitary landfills in the study area is more feasible.