The move is a step toward repairing the image of the world's largest planemaker, which has been severely dented by the crashes and its sometimes clumsy response to them.
Boeing is being investigated by global regulators and US lawmakers over the development of the 737 MAX and is the defendant in more than 100 lawsuits by the families of victims of a Lion Air crash in October and Ethiopian Airlines in March, which together killed 346 people.
The multiyear payout is independent of the lawsuits and would have no impact on litigation, a Boeing spokesman said.
The $100 million is meant to help with education and living expenses and to spur economic development in affected communities, Boeing said, without specifying which authorities or organizations would receive the money.
It also said it will match any employee donations through December.
"The families and loved ones of those on board have our deepest sympathies, and we hope this initial outreach can help bring them comfort," said Boeing Chief Executive Officer Dennis Muilenburg.
'SORRY WORKS'
Following an initial response that public relations experts criticized as stilted and lawyer-driven, Boeing has been on a charm offensive, with executives at the Paris Airshow last month repeatedly apologizing for the loss of life. Muilenburg posted regular Twitter updates on efforts to safely return the 737 MAX to service and win back public confidence.
"The Boeing brand is worth far more than $100 million and the board and executive leadership understand that is what is at stake," said William Klepper, a Columbia Business School professor.
The 737 MAX was grounded worldwide in March and Boeing has been working on a fix for software that has been identified as a common link in both crashes.
Boeing has been working on an upgrade for a stall-prevention system on the plane known as MCAS.
Regulators must approve the fix and new pilot training before the 737 MAX can fly again.
In a video posted on Twitter on Wednesday, Muilenburg said the company was continuing to work with regulators to address safety concerns, noting: "It's important we take the time necessary."
Last month, regulators identified a new problem that will delay commercial flight for the jets until October at the earliest.
Meanwhile, legal experts said a more apologetic tone by Boeing can appeal to families of victims and encourage them to settle, an approach similar to a "sorry works" strategy that hospitals use in malpractice lawsuits.
Boeing is in settlement talks over the Lion Air litigation and has separately offered to negotiate with families of Ethiopian Airlines victims, but some families have said they are not ready to settle, exposing the planemaker to a lengthy court battle.
"What families really want to know is why this happened," said Justin Green, a New York-based attorney representing several of the Ethiopia crash victims. "Could this have been avoided?"