Pia Maria Nalli (10 February 1886 – 27 September 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.

[5] After finishing her studies, Nalli assisted Bagnera in Palermo in 1911 and then began working as a school teacher.

She completed a habilitation thesis in 1914 on the theory of integrals, and continued to work on Fourier analysis and Dirichlet series for the next several years.

During this time Nalli continued her research, completing her thesis "Esposizione e confronto critico delle diverse definizioni proposte per l'integrale definito di una funzione limitata o no",[2] a study of the theory of the integral based on recent work on the subject by Émile Borel, Henri Lebesgue Charles de la Vallée Poussin, Giuseppe Vitali and Arnaud Denjoy.

At around this time, perhaps encouraged by Tullio Levi-Civita, she switched her research focus from functional analysis to tensor calculus.