We examined lines of arrested growth (LAG) in femurs from 20 individuals of the sand lizard Psammodromus algirus sampled from the north of Tunisia (North Africa). The number of the LAGs reached a maximum of three. The instant speed of linear growth in the first year was 6.6×10^–2 mm/day and 3.76×10^–2 mm/day the second year. The diameter of the marrow cavity was significantly larger in female (334.52 µm±115.68 µm) than in male (324.42 µm±114.2 µm). The growth rate observed in P. algirus followed the known growth pattern in lacertid lizards and the difference in the diameter of the marrow cavity between males and females may be related to a sexual dimorphism.