A scroll compressor and an air conditioner including a scroll compressor are provided. The scroll compressor may include a casing, a fixed scroll, an orbiting scroll, and an injection passage. The fixed scroll may further include a first injection hole and a second injection hole formed on a spiral flow passage, and a third injection hole and a fourth injection hole formed on the spiral flow passage at a position inwardly rotated by about 360 degrees from the first injection hole and the second injection hole along the spiral flow passage. The first injection hole and the third injection hole may be formed on an outer lane of the spiral flow passage, and the second injection hole and the fourth injection hole may be formed on an inner lane of the spiral flow passage.