Results of an acoustic study of voiceless fricatives in seven languages are presented. Three measurements were taken: duration, center of gravity, and overall spectral shape. In addition, formant transitions from adjacent vowels were measured for a subset of the fricatives in certain languages. Fricatives were well differentiated in terms of overall spectral shape and their co-articulation effects on formant transitions for adjacent vowels. The center of gravity measurement also proved useful in differentiating certain fricatives. Duration generally was less useful in differentiating the fricatives. In general, results were consistent across speakers and languages, with lateral fricatives displaying the greatest interlanguage variation in their acoustic properties and /s/ providing the greatest source of interspeaker variation.