It reported a fourth-quarter net profit of 1.35 billion Czech crowns ($54.27 million), up 33 percent from pro-forma results a year earlier.
Analysts polled by Reuters had expected a profit of 1.29 billion profit.
O2, majority-owned by Czech investor Petr Kellner's investment group PPF, said revenue rose 0.4 percent to 9.7 billion crowns.
It said it would start its share buyback on January 28, ready to buy up to 130,745 shares a day. The company announced the programme in December, setting a price range at 10-297 crowns, planning to buy up to 4 percent of own stock.
The company spun off its infrastructure assets last year.