Hasmukhray Vrajlal Yajnik (12 February 1938 – 10 December 2020), better known as Hasu Yajnik, also spelled Hasu Yagnik was an Indian Gujarati language novelist, short story writer, critic, editor, folklorist and children's writer.

Born and educated in Rajkot, he served as a professor of Gujarati in various government colleges in Gujarat.

Yagnik was born on 12 February 1938 in Rajkot (now in Gujarat) to Vrajlal Yajnik and Pushpaben (Prasannaben).

[3][4] His father was clerk in British Agency in Rajkot while his grandfather Govindalal was a survey officer in Palitana State.

[1][2] Yajnik had written under various pen names: Upamanyu, Pushpadhanva, B. Kashyap, Vajranandan Jani and Shridhar.

[3] His populist novels with simple themes and language include Dagdha (1968), Highway Par Ek Rat (1981), Biji Savarno Sooraj (1982), Sol Pachhi (1986), Neera Kausani (1987).

[4] Mandani Maya (1985), Ek Jubanimanthi (1985) and Pachhitna Paththaro (1985) are his short story collections.

[4] He had notated traditional devotional songs edited by Harivallabh Bhayani in Hari Ven Vay Chhe Re Ho Vanma (1988).