This study analysed the prevailing oral health-related knowledge, attitudes and behaviour of children entering school in Tanzania. The assessment was conducted in a random sample of 200 children who were newly enrolled in first grade in urban and rural areas of the Ilala district, by means of interviews, oral hygiene check-ups and practical exercises. Toothbrushing was a prevalent habit among these children, but its efficiency was low. Modern toothbrushes were commonly used and preferred to wooden toothbrushes. Toothpaste was considered essential and commonly used in urban areas but, instead, charcoal or ash were used in rural areas. The children's sugar consumption was low, but they widely valued sugary snacks. They had low awareness of gum disease and tooth decay, and poor knowledge about the causes and prevention of these diseases. These findings indicate gaps in the children's oral health ideas and practices acquired from home. The ongoing school oral health education is a crucial opportunity for the required improvements.