MacKenzie Scott, one of the richest women in the world, said Tuesday she would give $2.7 billion to 286 organizations, in her latest philanthropic move.

In a Medium post, Ms. Scott said she and her husband, Dan Jewett, along with researchers, administrators and advisers, spent much of the year identifying historically underfunded nonprofits that work in neglected areas.

“We chose to make relatively large gifts to the organizations…both to enable their work, and as a signal of trust and encouragement, to them and to others,” said Ms. Scott, who was formerly married to Amazon.com Inc. founder Jeff Bezos.

The organizations receiving money include community-based groups such as the Asian Pacific Community Fund and Memphis Music Initiative; places of education, such as El Paso Community College and California State University, Northridge; and organizations fighting discrimination, such as Black Led Movement Fund and Funders for LGBTQ Issues.

Ms. Scott wrote that she wished these announcements would focus less on the donors, like herself and her husband, and more on the organizations that were being funded. “Putting large donors at the center of stories on social progress is a distortion of their role,” she wrote.

Ms. Scott said she is increasingly concerned about vast quantities of wealth being in the hands of a small group of people. “In this effort, we are governed by a humbling belief that it would be better if disproportionate wealth were not concentrated in a small number of hands, and that the solutions are best designed and implemented by others,” she said.

Ms. Scott is the world’s 22nd-wealthiest person, worth an estimated $59.8 billion, according to the Bloomberg Billionaires Index.

Attempts to reach Ms. Scott for further comment were unsuccessful.

Last year, Ms. Scott made two similar announcements, giving away billions of dollars to hundreds of organizations that include historically Black colleges and universities, Covid-19 relief groups, food banks and groups working in education.

In 2019, Ms. Scott announced that she had signed the Giving Pledge, founded by Bill Gates, Melinda Gates and Warren Buffett. The pledge encourages the world’s richest individuals and couples to give more than half of their wealth to philanthropy or charitable causes, either during their lifetime or in their wills.

“My approach to philanthropy will continue to be thoughtful,” Ms. Scott wrote at the time. “And I will keep at it until the safe is empty.”

Corrections & Amplifications
Warren Buffett is one of the founders of the Giving Pledge. An earlier version of this article incorrectly spelled his last name as Buffet. (Corrected on June 15)

Write to Talal Ansari at Talal.Ansari@wsj.com