The origin of electromagnetism has been a recurring question since the discovery of electricity. In the 19th century, Maxwell unified electricity and magnetism into a single electrodynamic theory described by Maxwell’s equations. This was followed by the discovery of the electrodynamic force on a moving charge by Lorentz. Later, Einstein demonstrated that magnetism and the Lorentz force can be considered a relativistic effect. However, despite these important theories, there is at present no physical theory that identifies the single fundamental cause of all known classical electromagnetism. In an attempt to identify this single fundamental cause, this paper shows that classical electromagnetism can be considered as effect of scalar waves emanating from charges. It is shown in this paper that Coulomb’s law, Maxwell’s equations, the magnetic and electric field, the Lorentz force, and the Lienard-Wiechert potentials, can all be derived only from this single hypothesis that scalar waves are emitted by the charges. In addition, it was shown that the Lorentz transformation can also be derived from this hypothesis of scalar waves. To achieve this, an important new quantity was introduced: the momentum of the scalar waves. It was shown that the force caused by these scalar waves is simply the time derivative of this momentum. It was also shown that both the Lorentz force and the Coulomb force can be represented as the time derivative of the scalar wave momentum.