Tone‐on‐tone masking patterns from simultaneous and forward masking paradigms are dramatically different. It has been suggested that some of this difference is an effect of suppression, presumably present only in the simultaneous‐masking data. To study this. suggestion psychophysical tuning curves were measured using simultaneous and forward‐masking techniques and measures of suppression were obtained from the same subjects using Houtgast's two‐component forward‐masking paradigm. Both normal and hearing‐impaired listeners were tested. With normal listeners, simultaneous and forward‐masked tuning curves were different in the frequency regions where suppression was most evident. Similar results were obtained from hearing‐impaired listeners in regions of normal sensitivity. However, in regions of decreased sensitivity, simultaneous and forward‐masking tuning curves were the same and no suppression was evident. These results suggest that much of the difference between simultaneous and forward‐masking data is a result of suppression. [Work supported in part by NIH Grant NS12045.]