A miter saw is a saw used to make accurate crosscuts and miters in a workpiece by positioning a mounted blade onto board. A miter saw in its earliest form was composed of a backsaw in a miter box, but in modern implementation consists of a powered circular saw that can be positioned at a variety of angles and lowered onto a board positioned against a backstop called the fence.

Powered miter saws also cut bevels into a workpiece by adjusting the vertical tilt axis of the upper portion of the machine while the table lats flat horizontally. Miter saws which axis can be tilted in a single direction are known as a single compound miter saw. If the axis can tilt both lefts and right it is known as a double bevel compound miter saw. Some are equipped with a sliding rail system or have a pivot arm to cut wider workpieces when laid flat on the table of the saw and flush against the fence. This is known as a sliding compound miter saw.

Miter saws are primarily used for cutting wood trim and molding, but can be used to also cut metal, masonry, and plastics as well via the appropriate type of blade is used for the material being cut.