Publisher Summary The eye movements of readers are affected by both the meaning dominance of an ambiguous word and whether prior sentence context disambiguates the meaning. These findings have been used to support claims about the role of linguistic constraints on word identification. The adequacy of these claims has not been evaluated, that is, it is not known if the assumptions that have been made to account for the effects of lexical ambiguity resolution on eye movements are sufficient to explain these effects. This chapter discusses the E-Z Reader model of eye-movement control during reading that is used as a framework to evaluate the theoretical assumptions that have been developed to explain lexical ambiguity resolution. This modeling exercise is informative because it demonstrates that not all accounts of lexical ambiguity are equally viable, and because it suggests further constraints on the types of cognitive processes that drive eye movements during reading.