Both deafness and sign language experience impact the distribution of visual attention, and either factor could affect reading span size, the area around fixation from which useful information is obtained. In contrast to the typical asymmetrical span (smaller on the left), deaf signers have a larger leftward span than skill-matched hearing readers. We investigated whether this enhanced span is due to changes in visual attention associated with early deafness or sign language experience (right-handed signs fall in the left periphery). A gaze-contingent moving-window paradigm was used to assess the leftward reading span of hearing early signers, deaf early signers, and hearing non-signers with similar reading abilities. The size of the leftward span for deaf and hearing signers was the same (10 characters), and was larger than that of hearing non-signers (4 characters). Thus, early (pre-literacy) sign language exposure is the source of the larger leftward span in deaf signers.