The effect of semantic neighborhood on the processing of ambiguous words was examined in two lexical decision experiments. Semantic neighborhood was defined in terms of semantic set size and network connectivity. In Experiment 1, the variables of semantic set size, network connectivity, and ambiguity were crossed. An ambiguity advantage was observed only within small-set low-connectivity words. In Experiment 2, the effect of network connectivity on the processing of words of high and low meaning relatedness was examined. Participants responded more rapidly to words of high meaning relatedness, relative to words of low meaning relatedness, but only within high-connectivity words. These results are interpreted within a framework in which both semantic feedback processes and meaning-level competition can affect the recognition of semantically ambiguous words.