The World Association of Theoretical and Computational Chemists (WATOC) is a scholarly association founded in 1982 "in order to encourage the development and application of theoretical methods" in chemistry, particularly theoretical chemistry and computational chemistry. It was originally called the World Association of Theoretical Organic Chemists, but was later renamed the World Association of Theoretically Oriented Chemists, and in 2005 renamed once more to the World Association of Theoretical and Computational Chemists.

Peter Malcolm Wallace Gill is a New Zealand theoretical and computational chemist known for his contribution to density functional theory (DFT). He is an early and main contributor to the computational chemistry software Q-Chem and was the president of the company during 1998–2013. He is especially known for developing the PRISM algorithm for evaluating two-electron integrals and linear-scaling DFT, as well as self-consistent field method for excited state electronic structure.