Abstract: The invention relates to a cylinder head (1) for an internal combustion engine, with a prechamber (2) which is arranged in the cylinder head (1) and is defined by an inner wall surface (11) of a prechamber wall (5), wherein the prechamber (5) comprises a first chamber portion (3) and a second chamber portion (4), wherein the first chamber portion (3) has a greater maximum diameter (D) than the second chamber portion (4), wherein at least one ignition device (16) opens into the first chamber portion (3), and the second chamber portion (3) comprises at least one overflow channel (7) for the passage of flow into a combustion chamber (8) which adjoins a fire deck (6). Am improved dissipation of heat can be achieved if at least one inner wall surface (11) of the first chamber portion (3) comprises at least one first flattened portion (13).