Abstract: A strap winder (10) is provided for winding up an elongated strap (58). The strap winder (10) is actuated by a power-operated driver, e.g., a pneumatic torque or a wrench (12) or an electric, pneumatic or hydraulic motor (281) and includes a body (26) and a shaft (28) that is rotatably supported by the body (26). The shaft (28) has, at one end, a slot (52a) configured for receipt of a strap (58). The other end of the shaft (28) is configured to connect with the power-operated driver and a guide plate (30) is provided that is supported by the body (26) and extends is a direction that is generally perpendicular to a longitudinal axis of the shaft (28). An optional guard plate (286) is pivotably mounted in parallel relation to guide plate (30) to protect the user from inadvertent contact with the rotating shaft (28) or the strap thereon. When winding is done, the guard plate (286) can be pivoted out of the way so that the coiled strap (58) can be removed from the shaft (28).