A snow retention system is a special barrier, grille, beam, or other device which holds snow or ice on a sloping roof so that it does not fall and injure or create nuisance for persons or property (e.g. cars) below the roof's edge. The barrier can have openings in it, allowing snow to fall through but in smaller, more harmless pieces.

These are sometimes required on roofs in snowy areas with photovoltaic panels installed, because snow sometimes tends to accumulate in large quantities around the panels.

The device retains snow or controls how it falls from the sloping roof. Automatic de-icing removes or melts snow and ice instead. An ordinary roof slope can shed snow without providing the barrier or holding device that defines snow retention.