The annual ceremony marked 29 years since Chinese authorities used tanks and soldiers to clear the square that had been occupied for weeks by students and workers.
Estimates by scholars and human rights advocates vary over how many people died in the crackdown, with figures ranging from the hundreds to the thousands.
The Hong Kong ceremony included speeches, a eulogy for the victims and a moment of silence. Videos of the Tiananmen protests and crackdown, including images of the iconic "tank man" protester, were shown on a giant screen.
Also visible at the venue for the protest, a local park named after Queen Victoria, was a mock-up of the "Goddess of Democracy" statue that became a symbol of the 1989 protests.
Hong Kong police estimated that as many as 17,000 people participated in the vigil Monday at its peak, down slightly from last year's 18,000. Rally organizers, meanwhile, claimed more than 100,000 took part.
Freedom of speech and assembly in Hong Kong are guaranteed under a Basic Law, or mini-constitution, worked out by British and Chinese officials.
British rule ended and Hong Kong became a special administrative region of China on July 1, 1997. Beijing promised that the so-called one country, two systems framework would be unchanged for 50 years.
Though Hong Kong citizens are able to exercise rights their mainland brethren cannot, frustrations have risen in recent years over a desire for a more direct say in local politics.
The global trade and finance center was rocked in 2014 by student protests calling for more democracy amid perceptions the central government in Beijing has increasingly encroached on local freedoms and autonomy despite the "one country, two systems" guarantee.
Benny Cheung, a 20-year-old university student from Hong Kong attending the vigil for the first time, said he is growing concerned as the clock ticks on China's promise.
"What will happen in Hong Kong," Cheung said he wonders in thinking what the city will be like when the five-decade period ends in just over 29 years.
The public remembrance in Hong Kong is in stark contrast to mainland China where Tiananmen commemorations are forbidden. Security in Beijing is tight in the days leading up to the anniversary.
"It is an event that remains taboo on the mainland," the local South China Morning Post newspaper said in an editorial Monday about the Hong Kong vigil.
Nearly 30 years after the Tiananmen protests were crushed, the issue remains a sore point between China and western democracies.
US Secretary of State Mike Pompeo issued a statement on Sunday recalling the "violent suppression of peaceful demonstrations" and urging China to provide an official tally of victims.
"We join others in the international community in urging the Chinese government to make a full public accounting of those killed, detained or missing," Pompeo said in the statement.