The senatorial scallop Chlamys senatoria (Gmelin, 1791) is a commercially important species but poorly understood in the Philippines. To provide biological information for future conservation and management, the ecology and reproductive biology of the senatorial scallop in Gigantes Islands, Carles, central Philippines were investigated from June 2013 to May 2014. Ecological parameters were monitored during the sampling period. Scallops were collected monthly from the catches of hired divers. The samples were measured, dissected, and processed for histological analysis and fecundity was also determined. Results demonstrated that C. senatoria occurs in rocky and sandy areas at 18–22 m. Physico-chemical parameters showed minimal variations over an annual cycle with sea bottom water temperature of 25–27°C, salinity of 33–35, pH of 8.0–8.4, and dissolved oxygen of 5.6–6.7 mg/l. Macroscopic and microscopic examination of gonads confirmed that this species is dioecious with no apparent external dimorphism. Five distinct gonad stages were observed: developing, ripe, spawning, redeveloping, and spent. This species spawns throughout the year (protracted or continuous) with a major peak from December to February and a minor peak in August. Size at maturity (50% of population is mature) was 57.1 and 59.5 mm shell height for males and females, respectively. Fecundity ranged from 5.8×10⁵ to 2.7×10⁶ oocytes/female with a mean of 1.3×10⁶ ± 5.4×10⁵ oocytes/female. Harvesting of scallops should be regulated during the months of peak spawning activities (August and December to February) and sizes should be limited to individuals >59.5 mm shell height.