Antibiotic resistance is an important public health problem. In this lecture, we will learn about what antibiotic resistance is and how it arises. Ultimately, antibiotic resistance occurs through a process of natural selection and evolution. In complex organisms such as humans, evolution takes place in thousands to millions of years. However, bacteria grow very quickly, have relatively high mutation rates, and outnumber us by the billions. Because of this, bacteria that are exposed to antibiotics can develop resistance in a matter of days. Faced with these odds, how can we tackle the growing problem of antibiotic-resistant infections? We will end by discussing whether we can use our knowledge of how resistance evolves to develop new therapies that could help to slow the emergence of resistance.