Increasing popularity of oat was accompanied with the introductions of many new cultivars for the last few decades. The aim of this study was to characterize the growth and developments of Kahraman, Kucukyayla, Yeniceri, Sebat, Otag and Dirilis oat cultivars using sigmoidal growth models. Growth data comprised of weekly observations of dry weights and growth stages with three samplings for two consecutive years. Results indicated that the growing season were the determining factor for the dry matter accumulation until the stem elongation stage since genotype differences became apparent only in the later stages. Sigmoidal growth models were successfully fitted to the growth data, and allowed for further evaluations. Goodness of fit statistics implied that Logistic, Logistic Power and Ratkowsky models were the best fitting growth models to explain dry matter accumulations of oat cultivars. Analysis also showed that Otag, Yeniceri and Sebat cultivars reached the highest dry matter accumulations. Point of inflections on the Logistic models indicated that Kucukyayla and Kahraman were the earliest cultivars in the Marmara region. Comparison of cultivars by using the growth models proved to be informative in terms of understanding the genotypic variation.