A worker bee is any female (eusocial) bee that lacks the full reproductive capacity of the colony's queen bee; under most circumstances, this is correlated to an increase in certain non-reproductive activities relative to a queen. While worker bees occur in all eusocial bee species, the term is rarely used (outside of scientific literature) for any bees other than honey bees.

Honey bee workers gather pollen into the pollen baskets on their back legs and carry it back to the hive where it is used as food for the developing brood. Pollen carried on their bodies may be carried to another flower where a small portion can rub off onto the pistil, resulting in cross pollination. A significant amount of the world's food supply, particularly fruit, depends greatly on crop pollination by honey bees. Nectar is sucked up through the proboscis, mixed with enzymes in the stomach, and carried back to the hive, where it is stored in wax cells and evaporated into honey.