Bovine mastitis is an important disease in the dairy industry worldwide, and streptococci are among the most important pathogens of this disease. In this study, we investigated the in vitro antibiotic resistance of Streptococcus (Sc.) dysgalactiae, Sc. agalactiae, and Sc. canis from quarter milk samples (QMS) over a 10-year period, between 2012 and 2022, in Bavaria, Southern Germany. Overall, these three species were mostly sensitive to the most commonly used antimicrobials, including β-lactams. However, among the three pathogens, Sc. agalactiae had the highest percentage of resistant isolates against various antibiotics.