She spoke during Union Day celebrations in Panglong, the same place where her father, independence hero General Aung San, signed a peace deal with ethnic groups in 1947.
Suu Kyi and her National League for Democracy party promised peace would be their top priority despite conflicts between ethnic groups and the military.
In recent months, critics have slammed Suu Kyi for not speaking out against military airstrikes and human rights abuses in ethnic areas.
Skirmishes, particularly in the north where Kachin insurgents are fighting the army, have displaced more than 100,000 civilians since 2011 alone.