The phrase “Big Bang theory” can refer to two different things, and each has a different “creator.”

1. The scientific Big Bang theory (origin of the universe)

The modern Big Bang theory in cosmology was first clearly formulated by the Belgian priest and physicist Georges Lemaître in the late 1920s and early 1930s.

He proposed that the universe began from a very small, dense state he called the “primeval atom,” which then expanded—this is essentially what we now call the Big Bang.

A few extra key points:

  • Earlier mathematical models of an expanding universe were worked out by Alexander Friedmann , but he focused more on the math than on a physical explosion-like beginning.
  • The name “Big Bang” was coined later, in 1949, by astronomer Fred Hoyle , who actually meant it somewhat dismissively while defending a rival “steady‑state” model of the universe.
  • Over time, observations such as the expansion of galaxies and the cosmic microwave background made Lemaître’s idea the leading cosmological model.

So, if your question is about the cosmological theory , the best short answer is:

Georges Lemaître created the modern Big Bang theory, and Fred Hoyle later gave it the name “Big Bang.”

2. The TV show “The Big Bang Theory”

If you meant the TV sitcom “The Big Bang Theory,” then it was created by Chuck Lorre and Bill Prady.

They developed the premise about socially awkward but brilliant scientists and the people around them, and both served as executive producers and head writers.

Some quick facts:

  • The series premiered on CBS on September 24, 2007, and ran for 12 seasons.
  • Producer Steven Molaro later joined them as a key writer and executive producer.

TL;DR:

  • For the universe’s Big Bang theory : Georges Lemaître (with the label “Big Bang” coined by Fred Hoyle).
  • For the TV show “The Big Bang Theory” : Chuck Lorre and Bill Prady.

Information gathered from public forums or data available on the internet and portrayed here.