Sardar, more formally known as Monoj Kumar Sardar & Bros. (often abbreviated MKS), is a maker of traditional Indian musical instruments based in Kolkata, India. The workshop is a family operation run by four brothers, drawing on generations of instrument-building craft passed down within the Sardar family. Their output centers on classical Hindustani instruments built largely by hand from tonewoods and gourd resonators.

The brand's catalog spans sitars (including styles associated with the Ravi Shankar and Vilayat Khan schools, as well as electric sitar variants), tanpuras, surbahars, dilrubas, esrajs, harmoniums, and shruti boxes. Their 13-reed shruti boxes with side-mounted slide controls are among the most widely distributed Sardar products outside India, sold through retailers and on Reverb under the "Sardar" name, and are commonly used by yoga, kirtan, and meditation practitioners as well as classical musicians.

MKS instruments are stocked by specialist Indian-instrument retailers worldwide, including India Instruments, Maharaja Musicals, Tabla Sitar, and Musicians Mall, and the Sardar workshop is regarded as one of the larger established sitar and harmonium makers operating out of Kolkata's traditional instrument-making district.

Sardar has 2 products cataloged on Equipboard, including Harmoniums and Sitars.