In this study, multiple linear regression models were used to estimate the monthly average daily global radiation using nine different variables for Antalya, Turkey; the extraterrestrial radiation, solar declination, mean relative humidity, ratio of sunshine duration, mean temperature, mean soil temperature, mean cloudiness, mean precipitation and mean evaporation. The results showed that the models can estimate global radiation within relative error (\e\) of -5.7 and 3.9%, a mean error (MPE) of 2.0% and root-mean square error (RMSE) of 2.5% for Antalya.