DFN is a three letter acronym that may refer to:
Dehcho First Nations, one of the First Nations of North Western Canada Desert Fireball Network, a fireball camera network based in Australia Deutsches Forschungsnetz, the German national research and education network , Definition HTML tag Differential Frequency Noise (electronics) Dignity Freedom Network, formerly the Dalit Freedom Network Direct function (dfn), a way to define a function in the APL programming language Discrete Fracture Network model, a mathematical representation of fracture characteristics for hydromechanical numerical calculations in geology Doyle-Fuller-Newman model, a physics-based model used to predict the electrochemical dynamics of lithium-ion batteries Dual Flat No Lead, a style of integrated circuit package