It has recently been demonstrated that the modular symmetry offers an elegant solution to the longstanding flavor mixing puzzle This innovative approach considers neutrino masses as modular forms, dependent on a complex modulus parameter. In this talk, I will briefly review recent developments in modular flavor symmetries, including their theoretical motivations, the basic knowledge about modular transformations, the generic methodology to construct a modular-invariant flavor model, and the distinctions between modular flavor symmetries and traditional flavor symmetries. In addition, I will also talk about the modulus stabilization.