H-block or h-block may refer to: Maze (HM Prison), Belfast, where the prison blocks were built to a uniform H-shaped plan Anti H-Block, 1981 Irish Republican election label H Block, a compilation album by various Irish folk artists H Block (Hong Kong), a 1970s block design in Hong Kong H engine, an internal combustion engine having the cylinders in an H pattern
H-block in aggressive inline skating, part of the frame of the skate The 1915–1920 and 1995–2000 MHz radio frequency bands, used for wireless broadband communications; see
See also H-Blockx, German hardcore punk band