This invention discloses a radiation curable barrier coating composition for application to paper or paperboard substrates that can be applied using a conventional flexographic printing process. The coating composition includes one or more hydrophobic cycloaliphatic radiation curable monomers, one or more alcohol-functional waxes or sterols, and one or more other hydrophobic wax materials. The incorporation of these materials together lowers the MVTR of the coating compared to other radiation curable compositions while also generating improved, higher gloss. This invention also discloses a method to manufacture the coating composition and a preferred method to print the coating composition.