Pia Maria Nalli (February 10, 1886 – September 27, 1964) was an Italian mathematician known for her work on the summability of Fourier series, on Morera's theorem for analytic functions of several variables and for finding the solution to the Fredholm integral equation of the third kind for the first time. Her research interests ranged from algebraic geometry to functional analysis and tensor analysis; she was a speaker at the 1928 International Congress of Mathematicians.