Growth performance of 168 Awassi (A), Morkaraman (M), Tushin (T) purebred lambs and their crosses AxM, MxT, AxM and TxM reared under semi-intensive management in Turkey were evaluated. The lambs grazed on pasture for 84 days and were provided with a concentrate diet (1.5-2.0% of their live weight). Birth weight and average daily weight gain during the pre-grazing period for M, A, T, MxT, AxM and TxM crossbred lambs were 2.91, 3.61, 3.70, 4.30, 2.63, and 3.79kg and 186, 129, 160, 160, 163, and 168g, respectively. Corresponding estimates were 20, 15, 15, 17, 20 and 19kg for initial fattening weight; 168, 169, 160, 176, 174 and 184g for average daily weight gain on fattening, and 34, 30, 28, 32, 35, and 34kg for final fattening weight, respectively. The amounts of concentrate consumed per kg weight gain in addition to grazing on pasture for purebred and crossbred lambs were 1.89, 1.86, and 1.97 and, 1.78, 1.82, and 1.71kg, respectively. The genotype of lamb and type of birth significantly affected the birth weight. Besides the genotype and the type of birth, age of dam and sex had a significant influence on the average daily weight gain during the pre-grazing period. Average daily weight gain during the fattening period was significantly affected by sex.