Siak

Siak may refer to:


 * Asiagh (असियाग) (Siak (सियाक)), a gotra/clan of Jats found in India
 * Siunia dynasty, alternatively known as Siak, a dynasty that ruled part of what is now Armenia
 * Eric Low Siak Meng (born 1948), Singaporean Chinese politician
 * Siak Regency, a regency of Riau, Sumatra, Indonesia
 * Siak River, a river in Sumatra, Indonesia
 * Sultanate of Siak Sri Indrapura a kingdom in Siak Regency from 1723 to 1946
 * PS Siak, a football club based in Siak Regency