Johannes Nicolaus Brønsted (Danish: [joˈhænˀəs ne̝koˈlɛːus ˈpʁɶnsteð]; 22 February 1879 – 17 December 1947) was a Danish physical chemist who is best known for developing the Brønsted–Lowry acid–base theory; he developed the theory at the same time as (but independently of) Martin Lowry.

[4] His research gained worldwide recognition, resulting in four Nobel Prize nominations, a gold H. C. Ørsted Medal and being appointed as a fellow of the Royal Society and a member of the National Academy of Sciences.

[8] Almost simultaneously and independently, the British chemist Martin Lowry arrived at the same conclusion, thus the name Brønsted–Lowry acid–base theory.

He also developed some work about the effect of molecular size on the thermodynamical properties of hydrocarbons, polymers and colloids.

[7] He also worked with the Nobel prize winner George de Hevesy on isotope separation by fractional distillation.