This chapter provides an overview of experimental approaches for acute and chronic social defeat in male mice and how to test for the behavioral consequences of social stress using the modified hole board. The first part refers to acute social defeat describing the classical resident/intruder test. It summarizes the experimental protocols including behavioral characterizations of the animals. The second part describes various models of chronic defeat and chronic stress such as the sensory contact model, chronic psychosocial stress, social disruption, and repetitive social defeat. The third part is devoted to behavioral testing during/after stress using the modified hole board. Besides an up-to-date collection of protocols, troubleshooting approaches are provided.