Student-led protests against Myanmar's military rulers began on August 8, 1988 and were joined by hundreds of thousand of people, before an army crackdown the following month that killed more than 3,000.
"I would like you all to think about what has happened and not forget," Suu Kyi wrote in a guestbook at a Yangon monastery, where she was one of about 400 people to attend a remembrance ceremony.
The 66-year-old Nobel Peace Prize winner took part in a one minute silence and donated robes to the monks, an AFP reporter witnessed.
Suu Kyi, who had been living in London but returned to Yangon in 1988 to nurse her sick mother, was quick to take on a leading role in the pro-democracy movement, delivering speeches to the masses at the city's Shwedagon Pagoda.
The daughter of Myanmar's liberation hero General Aung San, the charismatic Suu Kyi commanded widespread support that alarmed the ruling generals, who ordered her first period of house arrest in 1989.
She has spent much of the last two decades in detention, and was released from her most recent seven-year stint in November, shortly after a controversial election from which she was excluded.
Her National League for Democracy party won a 1990 vote but was never allowed to take power.
On Monday she was joined by her 70-year-old security officer Win Htein, who also took part in the 1988 uprising and spent many of the subsequent years as a political prisoner.
"Today I remember all the people and students who lost their lives for democracy, not only in 1988. Also I always remember the student activists who started in 1988 and who are still in prison now," he told AFP.
Copyright AFP (Agence France-Presse), 2011