Pulsed ultraviolet laser induced surface reactions of chlorine on silicon were investigated. The predominant chlorination products were SiCl and SiCl2. Laser fluence effects could be clearly divided into three regimes: under ≊150 mJ/cm2a nonthermal reaction occurred, from 200–400 mJ/cm2thermal effects play a significant role, and above this vaporization and plasma formation dominate. Wavelength effects were also apparent. Fluence thresholds for the appearance of products varied with 351 nm having the lowest, 308 nm the highest, and 248 nm intermediate values. The effect of wavelength upon product ratios suggests that a competing process of chlorine photodesorption is accessed at 308 nm. Increases in dopant concentration yielded increased production of silicon chlorides. The results of combined variations in dopant concentration and wavelength indicate the presence of at least two distinct mechanisms—one involving initial photon‐substrate interactions, the other photon‐adsorbate interactions. Under all conditions studied silicon chloride production was linear in chlorine gas pressure.