Lithuanian parliamentarians also called on Turkey to reach a similar assessment of the tragic events of 1915. The number of dead is commonly estimated at one million, though estimates vary on either side.
The resolution was passed by 48 votes to none against. Three members of the Seimas abstained.
The speaker of the Armenian parliament, Artur Baghdasarian, reportedly sent a letter of thanks to his Lithuanian counterpart, Arturas Paulauskas.
Several governments and national parliaments have recognized the 1915 killings as genocide. The European Parliament has also recognized the slaughtering as stemming from a systematic policy of extermination.
But Turkish governments that took over from Ottoman rulers have always denied that the killings constituted genocide.