Tunisia's Tourism Minister Selma Elloumi Rekik and British Foreign Office official Tobias Ellwood laid down flowers to remember the victims of the shooting in the town of Port El Kantaoui south of the capital.
A priest then called out the names of the victims under the watchful eye of security forces, who were out in high numbers for the occasion.
Hotel employees as well as diplomats from Germany, Portugal, Ireland, Belgium and Russia -- whose countries also lost victims in the attack -- also attended the ceremony.
Tunisia, the birthplace of the Arab Spring, has suffered from a wave of jihadist violence since the 2011 revolution that ousted longtime dictator Zine El Abidine Ben Ali.
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The beach bloodbath was the second of two deadly jihadist attacks that dealt heavy blows to the country's vital tourism sector last year, following four years of decline due to political instability.
The shooting came just months after 21 tourists and a policeman were killed in another attack at the Bardo National Museum in Tunis. Both were claimed by IS.
The authorities implemented a state of emergency, which remains in place after it was extended for the fourth time on Monday.