"Happy Mother's Day to all the amazing Moms in my life," Affleck wrote. "Please share this video for the Mothers and Grandmothers in your lives in honor of their sacrifices, selflessness and courage."
The video, which was shot during Affleck's recent trip to the Democratic Republic of Congo, featured footage of moms and children in the Congo.
The 39-year-old thesp founded the Eastern Congo Initiative (ECI) in 2009, which focuses on helping the residents of eastern Congo develop community-based, local approaches to create a sustainable society.
"I want to say Happy Mother's Day to all the moms in my life--my mom, Chris, and my amazing wife, Jennifer, who is an incredible, spectacular, world-class mom, and I want to thank her," Affleck said in the video.
"And I want to say Happy Mother's Day to all the moms I've met in the Democratic Republic of Congo who are on this video that I hope you watch," he continued. "I urge you to share it, to post it to Facebook, to celebrate all the moms in the world, including the ones in your life, as well as those out there in the world working at the very hardest job there is every single day."