A wearable assistive device may include a main frame that covers a pelvis of a user, a subframe installed on a front surface of the main frame to secure a waist of the user, and a leg assembly installed at opposite ends of the main frame and formed to extend downward along each leg of the user to generate an assistive force that assists the user. The subframe may include a main waist support that supports a back of the user, a first support hingedly coupled to a first end of the main waist support to support a first side of the waist of the user, and a second support hingedly coupled to a second end of the main waist support to support a second side of the waist of the user.