The NLD won 346 of the 412 that were declared, with 64 more yet to be announced.
This comfortable victory will be a welcome boost for Nobel Peace Laureate Suu Kyi who has enjoyed a turbulent first term and struggled to meet high public expectations.
She is charged with developing a country that has endured nearly 50 years of isolation and decay under strict military rule, including years under house arrest.
This time the ballot was seen as a referendum on the government of Suu Kyi, which is extremely popular with us. But her reputation abroad has collapsed over charges of genocide against the country’s Rohingya Muslim minority, which she denies.
The main opposition party, the Army-backed Union Solidarity and Development Party (USDP), won 24 seats, according to the official partial results.
The USDP raised objections on Wednesday and demanded a new vote as soon as possible “in order to have free, fair, impartial and free from unfair campaigning” elections.
A USDP spokesperson could not be reached immediately for comment on Friday.
International and domestic observers said the voting went smoothly and without major irregularities.
The electoral commission said on Wednesday that all allegations of irregularities came from a minority of participants.
The NLD has also demanded proof of wrongdoing, while the military, in an earlier statement, said the election was successfully held.