This study was carried out to determine the quantitative effects of different light and temperature conditions on vegetative growth characteristics of pepper plant (Capsicum annuum L.) grown in greenhouses in different periods. Plants were grown under shaded and unshaded conditions in four different planting periods (May, August, October and March) in glass and plastic greenhouse. 50% transparent green polyethylene netting cover was used for shading. In the study, Çetinel 150 pepper variety was used. The effects of light and temperature on plant growth parameters (plant height, stem diameter, leaf number, total plant dry weight, leaf area, root weight ratio, stem weight ratio, leaf weight ratio, leaf area ratio, net assimilation rate and relative growth rate) were determined in detail. As a result of multiple regression analysis of the data obtained from all parameters, mathematical models were obtained and the models were converted to 3D graphics. The effects of temperature and light on all the parameters examined were explained depending on the light integral (70-1500 μmol m -2 s -1 ) and temperature (14-28 ° C) by using these graphs. As a result of the multi-regression analysis, it was found that there was a close relationship between actual and predicted growth parameters. The regression coefficients of the newly produced equations for growth parameters for pepper changed between 0.72 (stem weight ratio) and 0.99 (leaf number). The results obtained from the present study shown that the plant height and leaf area were increased curvilinearly with increasing temperature and decreasing light intensity. With the increasing temperature and light conditions, the stem diameter increased curvilinear. The optimum temperature for the relative growth rate (NBH) was determined to be between 24-27 ° C depending on the light intensity. With the results obtained from this research, the first step was taken to establish pepper production planning especially in controlled greenhouses.