In a poll at the open session of the parliament on Tuesday morning, Larijani secured 237 out of 276 votes.
The next candidate, Mostafa Kavakebian, trailed far behind with only 11 votes.
The vice speakers and members of the presiding board were also elected in the session.
Lawmakers also elected Massoud Pezeshkian and Ali Motahhari as the vice speakers of the new parliament.
There are 290 seats in the parliament, known in Iran as Majlis, 8 of which are still vacant.
The parliamentary elections were held on February 26, when more than 60 percent of some 55 million eligible voters cast their ballots at around 53,000 polling stations across the country.
The run-off votes were also held in late April to fill the remaining seats.