At a service at Dryfesdale Cemetery in Lockerbie, prayers were read, a moment of silence was held, and wreaths were laid before a memorial with the names of the 270 victims. Relatives of the victims and a representative of Queen Elizabeth II were among those attending.
"Scars from 30 years ago remain — they leave a mark that can never be removed," said the Rev. Susan Brown. "But while they will not disappear altogether, and while we would never want to forget the horrendous cost of that single hateful act, we realize all the more acutely the sweetness of life and the need for it to be lived to the full."
Most of those on board were Americans, including 35 students from Syracuse University in upstate New York.
Another memorial was being held later Friday at the university, and around 500 people are expected to gather at Arlington National Cemetery in Virginia, where a cairn made from Lockerbie stone stands in memory of those who were killed.
Many believe the atrocity was committed in revenge for the downing of an Iran Air passenger flight by a U.S. missile cruiser earlier in 1988.
Libyan intelligence officer Abdelbaset Al-Megrahi was convicted of the crime in a court in the Netherlands in 2001. He was the only person found guilty in the case. Al-Megrahi died of cancer nearly three years after he was released from a Scottish prison on compassionate grounds in 2009.
Three decades later, the investigation into the Pan Am bombing continues, with British prosecutors pledging to track down Al-Megrahi's accomplices.
Britain's Crown Office said Friday that prosecutors and police, along with their counterparts in the United States, are still investigating "with the sole aim of bringing those who acted along with Al-Megrahi to justice."