Tomio Kubota (久保田 富雄, Kubota Tomio) (6 December 1930 – 30 June 2020) was a Japanese mathematician working in number theory.

His contributions include works on p-adic L functions and real-analytic automorphic forms.

[3] His work on p-adic L-functions, later recognised as an aspect of Iwasawa theory, was done jointly with Leopoldt.

[4][5] He extended the concept of metaplectic group, in a way significant for arithmetic applications.

[6] This opened a field for later research on associated Dirichlet series and automorphic forms, and was a major step in the solution of Kummer's conjecture.