The majority are in the Roscommon area
Around 2,000 customers are without power following lightening strikes.
ESB Networks say the majority are in Roscommon, which will be restored by later tonight.
While around 400 customers in north county Dublin will be without power overnight.
Crews will work on the repair from first light on Wednesday.
You can see if your area is affected on the Power Check website.
It comes after Met Éireann issued a status orange weather warning for thunder earlier.