The theoretical understanding of electron transport in graphene and graphene nanoribbons is reviewed, emphasizing the help provided by atomic pseudopotentials (self-consistent and empirical) in determining not only the band structure but also other fundamental transport parameters such as electron-phonon matrix elements and line-edge roughness scattering. Electron-phonon scattering in suspended graphene sheets, impurity and remote-phonon scattering in supported and gated graphene, electron-phonon and line-edge roughness scattering in armchair-edge nanoribbons are reviewed, keeping in mind the potential use of graphene in devices of the future very large scale integration technology.