Kailas Nath Kaul (1905–1983) was an Indian botanist, naturalist, agricultural scientist, horticulturist, herbalist, plant collector and herpetologist, and a world authority on Arecaceae.

He is regarded as a vital influence behind his niece Indira Gandhi's proactive role in environmental protection by means of extensive legislative and policy interventions.

He directed the Institute until 1965, during which time it remained one of the world's five best botanical gardens, along with those at Kew (UK), Bogor (Indonesia), Paris (France) and New York (USA).

In the same period, he contributed to the development of the botanical gardens at Peradeniya (Sri Lanka), Singapore, Bogor (Indonesia), Bangkok (Thailand), Hong Kong, Tokyo (Japan), and Manila (Philippines).

In 1947, Kaul discovered fresh water aquifers in the princely state of Jodhpur in the Thar Desert, India, mainly by studying the spatial patterns of vegetation and depths of wells in the region.

He worked for several years on the conservation and management of floral biodiversity and the rejuvenation of the Mogul-era gardens in the state, and as the advisor to the Chief Minister on the subject.

Its decentralized, community-based development approach benefited subsistence and small-scale commercial farmers through the intensification and diversification of biomass production for food, fuel, fodder, fertilizers, medicines, timber, animal husbandry, aquaculture, soil amelioration, and bioaesthetics.

He also worked for the promotion of traditional sculpture, painting, and applied arts, and was elected as the President of the Lalit Kala Akademi of Uttar Pradesh in 1965.