High-resolution electron energy loss spectroscopy is a suitable tool for investigating phonons in graphene, due to its exceptional energy resolution in both the energy and momentum domains. In this chapter, we show that the experimental phonon dispersion of graphene can be used to estimate elastic properties and electron–phonon coupling. Novel coupling mechanisms of Dirac cone electrons in graphene with out-of-plane optical phonons of the graphene lattice, activated only whenever the graphene sheet is supported by a solid substrate, are also discussed.