The Moon Children are located inside the Moon on a Grassy Playfield. There are five children, four of which are running around the Tree in the center of the field, while the fifth sits at the bottom of the tree. The four running children each wear one of the boss Remains while the fifth wears Majora's Mask. The children are identical in height, clothing, and hair color, differing only in the mask they wear. Their gender is debatable but their haircut seems to indicate that they are male. They were created by Majora's Mask, made to appear the same age as Link. Despite their resemblance to the Happy Mask Salesman, he had never met them.
The four children ask for different amounts of Masks from Link. In return, they agree to play Hide-and-Seek with him, sending Link into a dungeon thematically similar to the one ruled by the boss whose mask they wear. After completing each dungeon, the child at the end of it will ask Link a question that concerns his beliefs about the world around them, after which the children will ask for more masks. After Link returns from each dungeon, the child disappears. However, if Link did not obtain all of the masks in the game, he cannot complete all of the dungeons and thus cannot get the Fierce Deity's Mask.
The final child wearing Majora's Mask will send Link into the final boss battle with the mask itself. He does not ask a question, but he mentions the absence of the other children if Link has completed the four dungeons. If Link obtained every mask in the game and gave them to the other children, the final one will comment on this and give Link the Fierce Deity's Mask. Before the final battle starts, he refers to it as the good guy playing against the bad guy, with Link being the bad guy. The fifth Moon Child's comment may indicate that the fifth Moon Child was temporarily possessed by Majora's Mask. The fact that the fifth Moon Child refers Link as an evil guy also indicates this, as it means that the fifth Moon Child's temporary possession indicates that Majora's Mask plans to destroy Link to prevent him from stopping The Moon from destroying Termina. 
- Viewing the extracted files from Majora's Mask 3D reveals that the face texture used for the Moon Children is that of the Happy Mask Salesman. In the original game, their faces had no texture.
- "I'm not too sure, but judging by the fact that they live on the moon, surely they cannot be normal children...? I have not met them in person, but I am pretty certain they must be some figment created by Majora's Mask. Perhaps they look like children because Link is himself but a child? Oh, look, they have the same hairstyle as me. So young, and yet so stylish!" — Happy Mask Salesman, Majora's Mask 3D Miiting with the Happy Mask Salesman, Miiverse (Archive), published March 13, 2015.
- "Ahhh... Nice weather...Isn't it? Masks...You have...a lot. You, too...Will you be... a mask salesman? Then I'll play with you. So...The masks...Give me some..." — Moon Child (Majora's Mask)
- "Thanks... You...You're nice person... Aren't you? Hide-and-seek...Let's play. All right...I'll...hide..." — Moon Child (Majora's Mask)
- "Your friends... What kind of... people are they? I wonder... Do these people... think of you... as a friend?" — Moon Child (Majora's Mask)
- "What makes you happy? I wonder...what makes you happy...does it make...others happy, too?" — Moon Child (Majora's Mask)
- "The right thing...what is it? I wonder...if you do the right thing...does it make...everybody...happy?" — Moon Child (Majora's Mask)
- "Your true face... What kind of... face is it? I wonder... The face under the mask... Is that... your true face?" — Moon Child (Majora's Mask)
- "... Everyone has gone away, haven't they?" — Moon Child (Majora's Mask)
- "You don't have any masks left, do you? Well, let's do something else." — Moon Child (Majora's Mask)
- "Let's play good guys against bad guys... Yes. Let's play that. Are you ready? You're the bad guy. And when you're bad, you just run. That's fine, right?" — Moon Child (Majora's Mask)
- NewSuperMoiWii, The Legend of Zelda: Majora's Mask 3D Unused Models, The Cutting Room Floor, published February 18, 2015, retrieved March 15 2015.
- Shesez, Boundary Break: Majora's Mask, YouTube, published June 30, 2016, retrieved July 26, 2016.