Monomers in a variety of dental materials may cause allergic contact dermatitis. While resin materials have been implicated in the onset of this condition, there is a paucity of evidence linking the condition to the resin-modified glass ionomers (RMGIs). This report documents a rare case of a dentist who developed allergic contact dermatitis following exposure to a RMGI. Contact dermatitis occurred despite the use of latex gloves, which were worn during the procedure. Both the acute and chronic stages of the condition were clinically represented. Patch testing was conducted to confirm the diagnosis. A no-touch technique and the routine use of nitrile gloves were subsequently adopted, which resulted in an overall decrease of the condition. Dentists, auxiliary personnel, and students should be aware of the possibility of sensitization to, and the development of allergic contact dermatitis not only from conventional resin materials, but also from the RMGIs.