Ecology of the fan-toed Gecko, Ptyodactylus hasselquistii, was studied in Naqbain village, Ha'il province, Saudi Arabia from January to December 2014. The maximal number of active geckos was recorded in spring and summer, with peaks of activity during the first three hours following sunset. Geckos showed irregular unimodal patterns of activity throughout different seasons; and exhibited diurnal activity most of the day time inside concrete buildings. More than a half number of geckos were active in direct artificial night lighting, 26.5%  in partial light, 12% in full darkness, 6% in daylight. The present geckos were usually encountered on fences and walls of buildings and they were occasionally seen on rocks and on the ground. Individuals frequently assumed positions at heights ranging from 15–­­ 350 cm above the ground. Lizards fed upon a wide range of food comprising insects, spiders, and plant materials. Coleopterans were the most important item in terms of number, volume, frequency of occurrence and the index of relative importance. P. hasselquistii displaced a sit – and – wait feeding strategy. Diversity of food items was greatest in spring and summer with the maximum number of prey per stomach recorded in spring. There was a seasonal variation of food items taken by P. hasselquistii. Adult geckos showed no significant difference in prey size selection. The reproductive season extends from April through August; and hatchling may occur in September and October. The youngest female having two oviductal eggs measured 61 mm snout-vent length (SVL). The relative clutch mass of females (RCM) varied from 0.015-0.096. The relative ova size (ROS) averaged from 0.13– 0.27. Testicular volume increased from March with peaks in April and May then decreased from July to November. The relative testes size (RTS) ranged from 0.022-0.09 and the relative testes mass (RTM) reached its maximum in May and varying from 0.0015-0.005. The youngest male having enlarged testes measured 61 mm, and was captured in May.