A Status Yellow Snow-Ice warning has been issued for Cavan, Donegal, Monaghan, Connacht and Louth.
Met Éireann has forecast wintry showers with some snow accumulations, sharp or severe frost and ice also.
The warning came into effect from earlier this morning and is valid until 11am tomorrow.
Temperatures are expected to fall to between -2C and -5C generally, with sharp or severe frost and icy stretches with black ice too.
Temperatures are expected to fall to between -2C and -5C generally (file photo)
Met Éireann is warning of hazardous travel conditions and poor visibility.
Meanwhile, a Status Yellow Low Temperature/Ice warning has been issued for Carlow, Dublin, Kildare, Kilkenny, Laois, Longford, Meath, Offaly, Westmeath, Wexford, Wicklow, and Munster.
That warning is valid from 5pm to 11am tomorrow.
In Northern Ireland, the UK Met Office has issued a Yellow warning for snow and ice for Antrim, Armagh, Down, Fermanagh, Tyrone, Derry with the potential to cause disruption to travel into Monday morning.
The warning is valid until midday tomorrow.