Semiconductor devices including a protection pattern for reducing galvanic corrosion and methods of forming the semiconductor devices are provided. The semiconductor devices may include a substrate including a keep out zone (KOZ) and a plurality of interconnections, which may be disposed outside of the KOZ on the substrate. The semiconductor devices may also include a through silicon via (TSV) in the KOZ. The TSV may pass through the substrate. The semiconductor device may further include a protection pattern, which may be electrically insulated from the TSV, may be disposed in the KOZ and may include a different conductive material from the TSV. A lower end of the protection pattern may be disposed at a level higher than a lower end of the TSV.