Sidh

Sidh may refer to:


 * Sidh, Gujrat, a village in the Gujrat District of Pakistan
 * Sidh community, a caste in western Rajasthan, India
 * Sidh, the abodes of the Aos Sí in Celtic mythology
 * Supersingular Isogeny Diffie–Hellman Key Exchange, post-quantum public key cryptographic algorithm; see Supersingular isogeny key exchange