This study used wrap-up effects on eye movements to assess the relationship between online reading behavior and comprehension. Participants, assessed on measures of reading, vocabulary, and spelling, read short passages that manipulated whether a syntactic boundary was "unmarked" by punctuation, "weakly marked" by a comma, or "strongly marked" by a period. Comprehension demands were manipulated by presenting questions after either 25% or 100% of passages. Wrap-up effects at punctuation boundaries manifested principally in rereading of earlier text and were more marked in lower proficiency readers. High comprehension load was associated with longer total reading time but had little impact on wrap-up effects. The relationship between eye movements and comprehension accuracy suggested that poor comprehension was associated with a shallower reading strategy under low comprehension demands. The implications of these findings for understanding how the processes involved in self-regulating comprehension are modulated by reading proficiency and comprehension goals are discussed.