Castlemania is the eleventh studio album by the American garage rock band Thee Oh Sees, the fifth album released by the band under the name "Thee Oh Sees" and their eleventh overall. It was released on May 20, 2011, by In The Red Records. It was the first of two studio albums to be made by the band in 2011, the other being Carrion Crawler/The Dream, which was released in November. It was recorded by a skeleton lineup of John Dwyer and Brigid Dawson along with some guest musicians.