Experiments using synthetic speech show that third‐formant transitions are cues for the perception of /b,d,g/. Detailed results are presented for a variety of third‐formant transitions paired with each of a number of second‐formant transitions in initial position before the vowels, /i/ and /æ/.The results obtained with various third‐formant transitions depend in part on the steady‐state level of the third formant, implying the existence of third‐formant loci analogous to those previously found for the first and second formants. The data of the present experiment are not sufficient to permit a specification of these loci.The effects of third‐formant cues are independent of the two‐formant patterns to which they are added. When a third‐formant cue enhances the perception of a particular phoneme, it typically does not do so equally at the expense of the other response alternatives.