The present study examined how proofreading and reading-for-comprehension instructions influence eye movements during reading. Thirty-seven participants silently read sentences containing compound words as target words while their eye movements were being recorded. We manipulated word length and frequency to examine how task instructions influence orthographic versus lexical-semantic processing during reading. Task instructions influenced both temporal and spatial aspects of eye movements: The initial landing position in words was shifted leftward, the saccade length was shorter, first fixation and gaze duration were longer, and refixation probability was higher during proofreading than during reading for comprehension. Moreover, in comparison to instructions for reading for comprehension, proofreading instructions increased both orthographic and lexical-semantic processing. This became apparent in a greater word length and word frequency effect in gaze duration during proofreading than during reading for comprehension. The present study suggests that the allocation of attentional resources during reading is significantly modulated by task demands. (Contains 1 table and 1 footnote.)