Shri Samarth Muppin Kaadsiddheswar Maharaj (23 April 1905 – 16 August 2001) was a guru in the Navnath tradition of Hindu philosophy.

Kaadsiddheswar was born on April 23, 1905 (Chaitra Sankashti day) in Linganoor village, Kolhapur district, Maharashtra state, India.

Shri Samarth Revannath (c. 1112 CE), one of the Navnath Parampara (The Nine Teachers) in the Indian Teacher-Disciple tradition, is considered the founder and the first Kaadsiddheshwar.

He established the Kaadsiddheshwar temple and math at Kanheri village in Karveer tehsil, Kolhapur district, Maharashtra state, India.

It is a vast campus with the central Shiva temple, Adhyatmik Center, and a complex of halls for discussions, residential hostels for devotees, and adjacent farms.

He gave extensive discourses on Hindu philosophy and the right way to live, which would lead him to Gyan Drishti and Vignayni Avastha.

These were organized on every full moon and on every major Hindu religious occasion, like the Sharavan Month, the Navratri and Ramnavmi.

However, the largest pravachans were organized on the three-day festival around Maha Shivarati day (February–March), where over 50,000 lakh devotees have been recorded at the Siddhagiri Math.