Sigmoidal growth curves are a useful tool for modeling experimental growth data when growth proceeds sigmoidally over time. When the changes in response have a double sigmoid growth pattern, it is convenient to employ a double sigmoid growth model to be able to describe the data well. In this paper, new double sigmoidal growth curves are presented based on the Burr Type XII distribution. In addition, for modeling the proposed curves, the procedure of summation of two single sigmoidal growth curves is considered. The proposed models namely the double Burr Type XII–logistic sigmoid growth model and the modified double Burr Type XII–logistic sigmoid growth model. Furthermore, to estimate the parameters of the proposed models, the non-linear least squares and the maximum likelihood methods are used. Moreover, a simulation study and an application are carried out to examine the performance of the proposed models compared to some classical double sigmoid growth models. The results indicate that the proposed model, modified double Burr Type XII–logistic sigmoid growth model is superior to the other existing models.