What is Maslow's hierarchy of needs?

Maslow proposed that human needs form a pyramid — lower needs must be met before higher ones: 1) Physiological: food, water, shelter, sleep (base). 2) Safety: security, stability, health. 3) Love/Belonging: friendships, family, intimacy. 4) Esteem: respect, recognition, confidence. 5) Self-Actualization: achieving full potential, creativity (peak). Criticism: the order isn't rigid — people can pursue higher needs while lower ones are unmet. Cultural differences exist. But it's useful for understanding motivation in education, workplace, and therapy.