Maria Novella Piancastelli is a retired Italian physicist whose research involves the experimental observation of electron configurations and shape resonance in atoms and molecules.
Piancastelli has a doctorate from Sapienza University of Rome. After professorships at the University of Rome Tor Vergata, Uppsala University in Sweden, and the Sorbonne University in France, she retired as an emeritus professor at the Sorbonne.
Piancastelli was elected as a Fellow of the American Physical Society (APS) in 2014, after a nomination from the APS Division of Atomic, Molecular and Optical Physics, "for studies of electronic structure and dynamics of core-excited and core-ionized atoms and molecules by means of x-ray spectroscopic tools". In 2022, Elettra Sincrotrone Trieste named her as an Elettra Fellow. She is also a member of the Royal Society of Sciences in Uppsala.