The authors describe the methods used and results obtained in a series of experiments designed to examine the effects of unilateral auditory masking upon the apparent position of a sound in space. Listeners were asked to locate various pure‐tone and complex‐sound signals delivered by a concealed loudspeaker while pure tone or complex masking stimuli were delivered to one ear by means of a single headphone. The results of these experiments indicate that masking can have a strong and consistent effect in pulling the apparent source of the free‐field signal toward the masked ear. The authors interpret this as evidence that binaural interaction is taking place and stress that most other methods of examining the phenomenon would fail to detect interaction between the types of stimuli used. The experimental data also indicate that intensity and frequency relations between signal and mask play a major role in determining the extent to which a masking stimulus will pull the apparent source of sound toward the masked ear; the effect is striking when the frequency spectrum of the mask covers that of the free‐field signal; the effect may still be evident, however, when signal and mask have no frequency components in common. The wide range of frequency relations between interacting signals and masks is consistent with the findings of neurophysiological and neuroanatomical studies of the auditory nervous system.