There is a pressing need in Iran for the translation of widely used speech-language assessment tools into Persian. This study reports the interjudge and intrajudge reliability of a Persian translation of the Stuttering Severity Instrument-3 (SSI-3) (Riley, 1994). There was greater than 80% interjudge and intrajudge agreement on scale scores for Frequency and Duration, 54% interjudge and 62.2% intrajudge agreement for "Physical Concomitants" and greater than 80% interjudge and intrajudge agreement for the Overall score. In conclusion, although percentage agreement for Physical Concomitant Behaviors was low, the Persian translation of SSI-3 shows otherwise acceptable interjudge and intrajudge reliability when performed under ideal conditions. Educational objectives: The reader of this article will be able to: (1) explain the process of test translation from the original language to another language; (2) summarize the process of determining interjudge and intrajudge reliability of the SSI-3 in preschoolers. (Contains 1 table.)