Robert J. Le Roy (September 30, 1943 – August 10, 2018) was a Canadian chemist. He held the distinguished title of University Professor at the University of Waterloo.

His work on the Morse/Long-range potential with his former student Nike Dattani of Oxford University was referred to as a "landmark in diatomic spectral analysis".^[1] In the landmark work, the C₃ value for atomic lithium was determined to a higher-precision than any atom's previously measured oscillator strength, by an order of magnitude. This lithium oscillator strength is related to the radiative lifetime of atomic lithium and is used as a benchmark for atomic clocks and measurements of fundamental constants.^[2]

• 1994 Rutherford Memorial Medal in Chemistry from the Royal Society of Canada^[3]
• 1995 J. Heyrovsky Honorary Medal for Merit in the Chemical Sciences from the Academy of Sciences of the Czech Republic.

• List of University of Waterloo people