Hisae Koyama (小山 ひさえ), sometimes referred to as Grandma Koyama or Mrs. Koyama, is Misae Koyama's 58 years old mother and Hiroshi Nohara's 58 years old mother-in-law. She is married to Yoshiji Koyama, and always fights over little things with him. Her appearances in Shin-chan episodes are usually with her husband. Like her husband, she looks down on the way Ginnosuke Nohara behaves, but she gets along well with Ginnosuke's wife Tsuru. She is angry with Musae, her youngest daughter. Her name means "eternal blessed." Most importantly, she is also the younger sister of Fusae.
- Yoshiji Koyama (husband)
- Masae Koyama (daughter)
- Misae Koyama (daughter)
- Musae Koyama (daughter)
- Hiroshi Nohara (son-in-law)
- Shinnosuke Nohara (grandson)
- Himawari Nohara (granddaughter)
- Fusae (older sister)
- Ginnosuke Nohara - her son-in-law's father, her grandchildren's paternal grandfather, and also her daughter's father-in-law.
- Tsuru Nohara - Her son-in-law's mother, her grandchildren's paternal grandmother, and also her daughter's mother-in-law.
- Semashi Nohara - Her son-in-law's older brother, her grandchildren's paternal uncle, and also her daughter's brother-in-law.