Photo: Yalonda M. James / The Chronicle Photo: Yalonda M. James / The Chronicle Photo: Yalonda M. James / The Chronicle Photo: Yalonda M. James / The Chronicle

Salesforce.org, the nonprofit arm of the San Francisco business-software company, will donate $18 million to education, cleanliness, homelessness and other Bay Area causes, the organization announced Tuesday.

The sum comprises $15.5 million for the San Francisco and Oakland Unified School Districts; $2 million for Hamilton Families, Larkin Street Youth Services and the San Francisco Food Bank; and $500,000 for the San Francisco Park Alliance.

“As a Bay Area-based company, a San Francisco-based company, we’re very concerned about issues facing San Francisco,” said Ebony Frelix, Salesforce.org’s executive vice president and chief philanthropy officer. “We take our responsibility really seriously.”

This year’s donations bring Salesforce’s giving to the San Francisco and Oakland school districts to more than $35 million and $14 million, respectively.

Besides money, Salesforce employees are given paid time to volunteer, and the company donates technology. Since February, Salesforce employees have spent 95,000 hours in volunteer service.

The foundation’s support is an “ongoing and long-term relationship,” according to Tomiquia Moss, CEO of Hamilton Families, which works to reduce homelessness among families in the Bay Area.

Hamilton Families’ relationship with Salesforce began in 2006, with a donation of computers. Since then, Salesforce employees have volunteered at the organization and the company has provided dozens of software licenses — with free technical support — to Hamilton staff to help the group use data to track support for families and identify best practices.

A major focus for the foundation has been supporting education and workforce development, according to Frelix, a San Francisco native. That’s hardly surprising, in a city bursting with fast-growing tech companies that cannot find enough workers. Salesforce.org has partnered with 42 schools in San Francisco and Oakland, and volunteers from the company have mentored and helped with IT for the districts. The company’s donations have let all San Francisco middle schools offer computer science courses, and enrollment in the courses is increasing, according to the district.

“One of the really unique things about the Salesforce giving is that they are really consistently working in partnership with the district to identify what outcomes are most needed to get to our goals to access and equity,” said Gentle Blythe, a San Francisco school official.

Some of the new donation will support Black Star Rising, a summer program to help African American students who are high achievers prepare for high school. Salesforce.org also backs year-round programs for elementary and middle-school students at 20 schools.

Public schools require everyone’s attention right now, Salesforce co-CEO Marc Benioff said, adding that improvements to public schools were critical to helping children get jobs in the “new economy.” Middle schools, he said, are especially important for student success, citing statistics that show interventions at that stage can lower drop-out rates later. Benioff personally has adopted Presidio Middle School and is paying to rebuild its playground.

“There’s so much opportunity but only for people who have strong education,” Benioff said. “That’s why we’re focused on a $100 million goal specifically for the San Francisco and Oakland public schools.”

Sophia Kunthara is a San Francisco Chronicle staff writer. Email: sophia.kunthara@sfchronicle.com Twitter: @SophiaKunthara