This paper aims to study Sonority Sequencing Principle (SSP) and Syllable Contact Law (SCL) in three-syllable words in Persian. For this purpose, Mahshid Moshiri’s Persian dictionary, along with the two-volume set of Moein Persian Dictionary were applied. After analyzing about one-hundred thousand words, only 269 three-syllable words with an initial syllable CVCC were found. Then, vowels and consonants sequences were obtained, and SSP and SCL were investigated by using Guskova Sonority Scale. The results of (c)vcc.cv(c)(c).cv(c)(c) show that short vowels of a e o are more inclined to appear at the nucleus of the first syllable than the long vowels of a i, and u. Also, among short vowels, ‘a’ has the priority. In other words, more sonorant vowels possess higher frequency. In addition, there is a fall in sonority in the first syllable of consonant clusters with a frequency of 212 (78% of the data), that shows the observance of SSP in intra-syllables sequence. It is also concluded that SCL in the first and second syllable boundaries is violated, so that there is a rise in sonority in 133 words.