Good Manufacturing Practice (GMP) is a set of rules for medicines manufacturers to follow so that their products are safe, effective, and of good quality. Everyone who works in a processing, quality control, packaging, or warehouse environment for a pharmaceutical or biotechnology company, or one of their contractors, must understand why GMP is important, how it applies to them, and how to comply with it. This short course explains what GMP is and why it is important, and it gives some lessons from history. It introduces the regulations and guidance documents that are the source of GMP rules. Finally, it touches on regulatory inspections and the consequences that can arise from failure to comply with GMP requirements.