I focused my studies on models for neutrino masses. Firstly, I studied 3 Type III Seesaw Models: a general case (in which an arbitrary number of triplets is added to the SM), the 3 triplets case (both for Normal Hierarchy (NH) and Inverted Hierarchy (IH) of light neutrino masses) and the 2 triplets case (again, both for NH and IH). As a result, I updated the constraints on the parameters of the models using the recently improved bounds on many observables (in particular, from nu-fit, PDG and Planck). After that, I studied neutrino mass models based on Non-Commutative Geometry (NCG). In particular, I studied an extension of the Connes’ model, i.e. twisted NCG applied to the SM. I evaluated the full fluctuation of the Dirac operator and the full fermionic action of the theory. I studied the physical meaning of the transition from Euclidean to Lorentzian signature in the inner product. I studied ways to extend the definition of the spectral action to the twisted case.