A compared study of leaves was led in three categories of carob tree (Ceratonia siliqua L., Leguminosae) from the province of Chefchaouen (NW of Morocco): unproductive "dkar" or spontaneous male, productive "dkar" or spontaneous female, "lanta" or grafted female. It shows that trees from the most favoured locations developed leaves with 21.9±3.45cm of length, 13.0±2.0l cm of width, 9±1 leaflets and 4.19±0.94cm of petiole length. The corresponding leaflets have 5.92±0.86cm of length and 3.65:t 0.52cm of width. Leaves of the unproductive "dkar" category are longer, larger and with petiole more developed; leaflets of this category are also longer, larger and more rounded when compared with productive "dkar" and "lanta" categories. The optimal leave development is observed in trees of "lanta" category aged from 10to 20 years. Leaves with 7-10 leaflets characterize more unproductive "dkar" category. Leaves partially 2-pinnate or 2-composed are highlighted exceptionally in the later category.