Magnetization dynamics has been a topic of busy research in the recent years as a detailed knowledge of the interplay of the microscopic processes involved in the magnetic damping is still missing or under debate due to their complexity. Furthermore, it is important to control the precessional frequency and the damping of the magnetization in technological relevant materials for applications in the field of spintronics. Therefore, from both, the fundamental and the technical point of view, a deeper insight in the fundamental dynamic processes in magnetic materials is desirable. In this thesis a detailed examination of the influence of rare-earth doping on the magnetization dynamics of magnetic films is presented. Doped Permalloy (Ni80Fe20), iron and cobalt films were investigated. Rare-earth materials (Gadolinium, Dysprosium and Holmium) were chosen as dopants for the studies. For the characterization of the dynamics different techniques, namely (Vector Network Analyzer-) Ferromagnetic Resonance, Time Resolved Magneto Optic Kerr Effect, Brillouin Light Scatteringand X-ray Magnetic Circular Dichroism, were used. The results show that rare earth doping is a reliable way to influence the dynamic behaviour of magnetic materials.