ß-Ti alloys are finding their way into applications across various engineering fields, such as aerospace and the biomedical field. These alloys stand out because of their excellent mechanical properties, corrosion resistance, and their potential to match the low elastic modulus of bone tissue, which is important for implants. However, these critical applications also require high strength, to prevent failure. Hence, this thesis explores strengthening by annealing in high-pressure torsion (HPT) processed ß-Ti-Nb-Zr alloys. Both severe plastic deformation processes like HPT and subsequent annealing are believed to have a positive effect on the material strength. While the hardening effects resulting from the grain size refinement induced by HPT is well-studied in ß-Ti alloys and generally well-understood, the anneal hardening phenomenon and its underlying mechanisms remain a topic of discussion in literature. For this, this thesis presents the first analysis of the anneal hardening kinetics in this ternary alloy system, aiming to contribute to a better understanding of the anneal hardening phenomenon.