The fretsaw is a saw used for intricate cutting work which often incorporates tight curves. Although the coping saw is often used for similar work, the fretsaw is capable of much tighter radii and more delicate work. It has a distinctive appearance due to the depth of its frame (typically between 10 and 20 inches), which together with the relatively short five inch blade makes this tool appear somewhat out of proportion compared to most other saws.

Compared to the coping saw it has much shallower blades, which are usually extra-fine (up to 32 tpi). This allows much tighter curves to be cut — with many blades even sharp corners are possible — but the blades are also much more fragile compared to that of a coping saw. Unlike the coping saw, the blade has a fixed orientation in relation to the frame. This means that the fretsaw is less useful when cutting long narrow components, but the increased depth of the frame does allow access much further from the edge of the board.

The fretsaw is similar in many respects to the scroll saw, which is essentially a powered fretsaw with a table. Blades between the two tools are usually interchangeable, and indeed scroll saws are often known as "fret saws" informally.