The PAI Terra Ranka coalition, led by the former ruling PAIGC party, won 54 of 102 seats in Sunday's poll, the electoral commission said on Thursday.
Madem G15, the party of President Umaro Sissoco Embalo, who dissolved parliament in May last year amid accusations of corruption, won 28 seats.
The result for now ends Embalo's plans to push through a change to the constitution that would have allowed him to consolidate power by ridding the country of its semi-presidential system.
The PAIGC party is against such a change.
The West African country of nearly 2 million people has seen frequent political turmoil, with at least 10 coups or attempted coups since it gained independence from Portugal in 1974.
A recent crash in the price of cashew nuts, its main export, has caused widespread poverty.
More than 20 political parties and coalitions sparred for seats in Sunday's polls as voters sought some stability.
Under the current political system, the majority party or coalition appoints the government, but the president has the power to dismiss it in certain circumstances.
That has led to political deadlock and infighting in the past.