Mahendranath Gupta (Bengali: মহেন্দ্রনাথ গুপ্ত) (14 July 1854 – 4 June 1932), (also popularly known as Shri M and Master Mahashay), was a disciple of Ramakrishna and a mystic himself.

In his autobiography, Yogananda noted that Gupta ran a small boys' high school in Kolkata, and he recounted their visits, as they often traveled to the Dakshineshwar Kali Temple together.

[1] Having a devotional nature, Gupta worshipped the Divine Mother in the form of Kali, and often reflected the wisdom of his guru Ramakrishna in his daily life and mannerisms.

Yogananda reverentially regarded Gupta's spirituality, calling him an "Incarnation of purity" and "the greatest man of humility I ever knew.

"[1] Mahendranath was born to Madhusudan Gupta and Swarnamayi Devi in a Bengali Hindu family of Baidya sub-caste in the Shimuliya (Shimla) locality of Calcutta (now Kolkata) of Bengal Presidency .

Eventually he became headmaster of Ishwar Chandra Vidyasagar's high school, where he was called "Master Mahashay"—just as he was often addressed in Ramakrishna's circle and later by Yogananda.

"[4][6][7] According to other traditional accounts, Mahendranath related that he may have met Ramakrishna for the first time when he was four years old and became separated from his mother while visiting the Dakshineswar Kali Temple.

Sometimes I had to keep awake the whole night...Sometimes I would keep on writing the events of one sitting for seven days, recollect the songs that were sung, and the order in which they were sung, and the samadhi and so on...Many a time I did not feel satisfied with my description of the events; I would then immediately plunge myself in deep meditation ...Then the correct image would arise...That is why in spite of the big gap in the physical sense, this story remains so fresh and lifelike in my mind as if it happened just now.

In his Autobiography of a Yogi, Yogananda dedicated an entire chapter to describing his friendship with Mahendranath, whom he referred to as "Master Mahasaya," which was along spiritual rather than academic lines.

Consumed by an unsophisticated passion for the Divine Mother, the saint no more demanded the outward forms of respect than a child.