An adjustable and lockable turnbuckle may include an elongated body having internal threading within a first end thereof. The turnbuckle may include a first extension rod having external threading configured to mate with the internal threading at the first end of the elongated body. The turnbuckle may include a first jam nut having internal threading and a skirt. The internal threading of the first jam nut may be configured to mate with the external threading of the first extension rod to tighten the first jam nut against the first end of the elongated body so that the skirt of the first jam nut is positionable about the first end of the elongated body. A first aperture may extend through the elongated body, the first extension rod, and the skirt of the first jam nut. Moreover, a first pin may be positioned within the first aperture.