She visited the school today with her Japanese counterpart, Akie Abe. About 300 children welcomed them with a school song.
Melania Trump wrote the first character of the Japanese word for "peace," as Akie Abe wrote the second.
The US first lady posed for photos, shook hands and exchanged high fives with the school children.
She is accompanying her husband, Donald Trump, on his first Asian tour as president, which began in Japan.
Yesterday, the two first ladies heard about the history of cultivated pearls at a jewelry shop in downtown Tokyo and joined their husbands for a private dinner at a Japanese steak house.