The Muscidae are a large and familiar family of true flies, commonly known as house flies and stable flies. They are found worldwide, with many species living close to humans and animals.

Members of this family are medium-sized flies, usually grey or black in colour, with large red eyes and short antennae. The common house fly (Musca domestica) is one of the most widespread insects on Earth and is often seen around homes, farms, and rubbish areas.

The larvae, or maggots, of Muscid flies usually develop in decaying organic material, such as animal dung, rotting vegetation, or waste. Some species, like the stable fly (Stomoxys calcitrans), are biting flies that feed on the blood of livestock and sometimes humans. Others, however, are harmless and play useful roles in breaking down waste materials.

Adult Muscid flies feed on a variety of substances, including nectar, decaying matter, and animal secretions. Because they are attracted to both food and filth, some species can spread disease-causing organisms, making them important in public health and sanitation.

In the UK, Muscid flies are very common, found in urban areas, farmland, and countryside habitats. While some are pests, others are beneficial decomposers and part of the natural cycle of decay and renewal.