The Pokhran-II tests were a series of five nuclear bomb test explosions conducted by India at the Indian Army's Pokhran Test Range in May 1998. It was the second instance of nuclear testing conducted by India; the first test, code-named Smiling Buddha, was conducted in May 1974.The tests achieved their main objective of giving India the capability to build fission and thermonuclear weapons with yields up to 200 kilotons. The then-Chairman of the Indian Atomic Energy Commission described each one of the explosions of Pokhran-II to be "equivalent to several tests carried out by other nuclear weapon states over decades". Subsequently, India established computer simulation capability to predict the yields of nuclear explosives whose designs are related to the designs of explosives used in this test.Pokhran-II consisted of five detonations, the first of which was a fusion bomb while the remaining four were fission bombs. The tests were initiated on 11 May 1998, under the assigned code name Operation Shakti, with the detonation of one fusion and two fission bombs. On 13 May 1998, two additional fission devices were detonated, and the Indian government led by Prime Minister Atal Bihari Vajpayee shortly convened a press conference to declare India as a full-fledged nuclear state. The tests resulted in a variety of sanctions against India by a number of major states, including the countries of Japan and the United States.

Many names have been assigned to these tests; originally these were collectively called Operation Shakti–98, and the five nuclear bombs were designated Shakti-I through to Shakti-V. More recently, the operation as a whole has come to be known as Pokhran II, and the 1974 explosion as Pokhran-I.