Five experiments are reported in which standard naming and tempo-naming tasks were used to investigate mechanisms of control over the time course of lexical processing. The time course of processing was manipulated by asking participants to time their responses with an audiovisual metronome. As the tempo of the metronome increased, results showed that (a) the rate of lexical errors increased, whereas the rate of regularization errors remained constant; (b) onset errors increased at a faster rate than body errors; (c) stimulus effects weakened on latencies, whereas they strengthened on durations and errors; and (d) naming durations decreased more slowly when stimuli were presented prior to the response cue. These results constitute evidence that time pressure in the tempo-naming task caused a compression in the time course of lexical processing. Compression is discussed in terms of threshold mechanisms and rate mechanisms of control.