Massive crowds gathered in the morning on a hillside for memorial prayers for relatives killed in the violence.
Others marched under the sweltering sun chanting, “We want justice” and “No more genocide”, some wearing white shirts bearing the words ‘Rohingya Genocide Remembrance’.
The commemorations took place amid heightened tensions in parts of the camps after security forces shot dead two Rohingya on Saturday, saying they were involved in the murder of a ruling party official.
More than one million people live in the camps in southern Bangladesh in the world’s largest refugee settlement. The majority having fled violence in 2017 that the United Nations says was executed with “genocidal intent”.