The counties affected are Carlow, Kildare, Kilkenny, Laois, Wexford, Wicklow, Offaly, Galway and all six Munster counties.
Met Éireann says there will be heavy rain overnight and into tomorrow morning which could lead to accumulations of 25 to 40 millimetres in places.
Thundery downpours are also possible along with localised spot flooding.
The warning comes into effect from 2am Monday morning, and will stay in place until just before midnight.
This follows a weather warning for Southern and Western counties yesterday which caused flooding in Co Cork.
After heavy rain over the past few days, some homes and businesses in the county have suffered damage from floods despite efforts to hold back the water with sandbags.
