The surgeon's knot is a surgical knot and is a simple modification to the reef knot. It adds an extra twist when tying the first throw, forming a double overhand knot. The additional turn provides more friction and can reduce loosening while the second half of the knot is tied.^[1] This knot is commonly used by surgeons in situations where it is important to maintain tension on a suture, giving it its name.^[2]

Surgeon's knots are also used in fly fishing, in tying quilts, and for tying knots with twine; it is particularly useful in tying raw meat with butcher's twine, as the wet meat creates similar risks of loosening as surgery. Some sources categorize the surgeon's knot as a bend, since it can be effective as such.^[3]

Like the reef knot, the surgeon's knot capsizes and fails if one of the working ends is pulled away from the standing end closest to it.^{[citation needed]}

• List of bend knots
• List of binding knots
• List of knots