Threaded sacro-iliac joint stabilization (e.g., fusion, fixation) implants and methods of implantation and manufacture. Some implants include a threaded distal region, an optionally threaded central region, and an optionally threaded proximal region. The distal, central, and proximal regions have lengths such that when the implant is laterally implanted across a SI joint, the distal region can be positioned in a sacrum, the central region can be positioned across an SI-joint, and the proximal region can be positioned in an ilium.