KMT-2023-BLG-1743L is a Sun-like G-type star (about 0.11 solar masses, 5,778 K), 7,130 light-years from Earth. KMT-2023-BLG-1743L b is a 20.0-Jupiter-mass companion, at 1.160 AU from its star, discovered in 2024 via microlensing. Microlensing detections occur when a foreground star's gravity briefly magnifies a background source, revealing planets that are otherwise too faint and distant to observe directly. KMT-2023-BLG-1743L b orbits at roughly the distance of Mars from the Sun. At 20.0 Jupiter masses, the companion lies near the dividing line between giant planets and brown dwarfs.