Momoko "Maruko" Sakura (さくらももこ Sakura Momoko?, まる子 Maruko)
Voiced by: Tarako
The title character, Maruko (born May 8, 1965), is a nine-year-old third-grade student raised in a relatively poor family of six. It is implied that the show is drawn by Maruko herself.
Hiroshi Sakura (さくらひろし Sakura Hiroshi?)
Voiced by: Yūsaku Yara
Maruko's father. He was introduced to Maruko's mother by her friend. His birthday is June 20, 1934, making him 40 years old during the series.
Sumire Sakura (さくらすみれ Sakura Sumire?)
Voiced by: Teiyū Ichiryūsai
Maruko's mother. Her birthdate is May 25, 1934. It is revealed in one episode that her maiden name is Kobayashi.
Sakiko Sakura (さくらさきこ Sakura Sakiko?)
Voiced by: Yūko Mizutani (1990-2016), Machiko Toyoshima (2016-)
Maruko's older sister. Her birthday is March 21, 1962, making her 12 in the series.
Tomozou Sakura (さくら友蔵 Sakura Tomozō?)
Voiced by: Kei Tomiyama (1990-1995), Takeshi Aono (1995-2010), Bin Shimada (2010-)
Maruko's kind but absent-minded grandfather. His birthday is October 3, 1898, making him 76 in the series. The author has said that she used her own grandfather as the model for Tomozou, but that his personality is the opposite of Tomozou's.
Kotake Sakura (さくらこたけ Sakura Kotake?)
Voiced by: Yūko Sasaki
Maruko's grandmother. She's wise and knows what's good for the human body and wears a traditional Kimono. She was born on April 4, 1904. Her name of Kotake was never known in the series until it appeared in a 4-panel manga (Yonkoma) on July 1, 2007.