The actress, 51, spent the day with Sami Sheen, 18, whom she shares with ex-husband Charlie Sheen, 56.
Sami shared a series of selfies featuring her and Richards out and about on Sunday.
"happy mother's day !! i love u so much mom. u have no idea how grateful i am to have u in my life 💗💐🥂," Sami captioned the carousel.
Richards added in the comment section, "Thank you Sami for an amazing Mother's Day. It means a lot to me. I know nana was at dinner with us she would never miss one of her favorite restaurants. 🙏🏻 Thank you & I love you so much❤️"
Richards' 16-year-old daughter Lola Rose Sheen, whom she also shares with the Two and a Half Men actor, also saluted Richards on Sunday.
Sharing a photo of her and Richards on her Instagram Story, Lola wrote, "happy mother's day mom. my best friend and role model. u forever have saved me. thank you for staying by my side no matter what. I'll always do the same. i will do anything for u thank u for being such a light in my life. you have the biggest heart out there. i wouldn't be the person i am today without you. i love u to the moon and the stars mom. us forever [three hearts Emoji]"
Richards posted the message on her Instagram Story, writing, "I love you.. thank you [praying hands Emoji]"
Her Mother's Day outing with Sami comes after she shared in February that their relationship is "strained" as Sami lives with Charlie.
"Honestly, I have a strained relationship with her," admitted Richards during an appearance on SiriusXM's Jeff Lewis Live. "It's very difficult. I know we'll get back to where we were eventually but right now, it is strained."
RELATED VIDEO: Denise Richards Honors Daughter Sami on 18th Birthday After Noting Their 'Strained' Relationship
Asked whether Richards was happy about Sami's current living situation, the star said, "Obviously I would love for her to live with me. She lived with me all these years."
"But I think it's very difficult raising teenagers now and especially in Los Angeles when there's access to everything. We didn't grow up with Postmates and Uber where you have everything that you want," she continues. "There are certain rules and I enforce them. And [at Sheen's], there's different rules at that house and that's okay."
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Richards said Sami is "not in school" and that she does not "agree with certain things" that Charlie does.
"But that's okay. We can agree to disagree," she told Lewis, noting that she's "not a strict mom," though she does have "rules and boundaries."