They have also called on other European countries to "express the same opinion".
Latvia MPs have officially declared Russia a "state sponsor of terrorism" amid the war in Ukraine.
The parliament declared its neighbour's actions amount to "genocide against the Ukrainian people", according to a statement published on Thursday.
MPs also called on other European countries to "express the same opinion".
Ukrainian foreign minister Dmytro Kuleba said he was "grateful" for the announcement and that the declaration was "timely".
Russia "uses suffering and intimidation as tools in its attempts to weaken the morale of the Ukrainian people and armed forces, and to paralyse the functioning of the state in order to occupy Ukraine," the parliament statement said.
The text was supported by all 67 lawmakers who took part in the vote in the 100-seat Saeima.
MPs have also accused Moscow of deploying internationally banned munitions "to spread fear and kill civilians".
The European Union member state stressed that Russia's invasion was carried out "with the support and involvement of the Belarusian regime" and urged further sanctions on Minsk.
Russia has issued blanket denials that its troops target civilians in Ukraine and insists it is not a war but a "special military operation".
Russian Foreign Ministry spokeswoman Maria Zakharova said the Latvian statement had no substance other than "primary xenophobia".
Compulsory military service
Latvia is set to reintroduce compulsory military service amid growing tensions with Russia following the invasion of Ukraine.
"We have no reason to believe that Russia will change its behaviour," defence minister Artis Pabriks told reporters in July.
The Baltic country has also banned public displays of the Russian military 'Z' and 'V' symbols, which have also been common on pro-Kremlin social media accounts.
Citizens are further prohibited from holding any events near a monument commemorating the Soviet army or its occupation of Latvia after World War II.
Latvia's parliament has joined Estonia to call on the European Union to stop issuing tourist visas to Russian and Belarusian citizens.
Some analysts have criticised the proposal as a "slippery slope" that could restrict the travel rights of innocent civilians.