Paul Rein (born Pauli Kaj Olavi Reinikainen, May 20, 1965) is a leading Swedish songwriter based in Stockholm. He was also a singer in the 1980s. He released italo disco singles such as "Lady-O", "Hold Back Your Love", "Stop (Give It Up)" and "Touch in the late 80's".

Rein is well known within the music industry for his hit songs which have enjoyed success on the Billboard charts, performed by vocalists such as Christina Aguilera ("Come On Over"), Jessica Simpson ("I've Got My Eyes On You"), Victoria Beckham, Mandy Moore, H & Claire, No Angels and Nikki Webster.