The transaction is being financed by the private equity group Innova Capital and should be finalised in Q1 2014.
However, it will require the agreement of the competition authority UOKiK. In a statement, Orange Polska says the sale of Wirtualne Polska will help it concentrate on its core activities.
Wirtualna Polska is the longest-established internet company in Poland and the second most popular, with over 13 million users.
Krzysztof Krawczyk, a partner at Innova Capital, said that merging Wirtualna Polska with O2 would create the largest internet company in Poland.
He added that the group is looking for more investment opportunities.