• Colin Mudford: A 12-year-old Australian boy determined to convince a cancer expert to treat his younger brother. He is kind, friendly, and adventurous.
• Luke Mudford: Colin’s 8-year-old brother who has terminal cancer. He is in Sydney for the entire novel, undergoing treatment.
• Alistair: Colin’s shy 13-year-old English cousin. While Colin is in London, Alistair becomes involved with Colin’s ambitious schemes to find a cure for Luke’s cancer.
• Aunty Iris: Colin’s aunt and Alistair’s overbearing mother. She is friendly toward Colin but is frightened that he is so open about Luke’s cancer.
• The Queen: Elizabeth II is unconcerned about Luke’s illness and does not respond to any of Colin’s letters and requests. A liaison officer writes a letter to Colin on her behalf at the end of the book, which Colin leaves in an aeroplane’s ashtray.
• Uncle Bob: Uncle Bob is Colin’s grumpy uncle. He thinks lowly of the British royal family, as well as the City of London. He often joins his wife in telling their son, Alistair, what to do.
• Ted Caldicot: A gay Welshman who listens to Colin about Luke as his partner, Griff, has a similar issue. Contrasted with the other adults in the book Ted is characterized as warm and open, especially about cancer.
• Griff Price: Ted’s partner of six years is being treated for AIDS-related cancer in the hospital. His favourite food is tangerines.

The book was adapted for the stage by Mary Morris in April 1992 and premièred at the Sydney Festival in the same year. Directed by Wayne Harrison, it received praise from its first performances, and has since been shown throughout the world, including England, Canada, Japan, the United States, Cuba, and Portugal. Two Weeks with the Queen won the Family Award in 1990.

Todd Morning, reviewing the book for School Library Journal, describes Colin as “incredibly feisty and brave”, and criticises the book’s “breakneck” pace, stating that this made it difficult to get to know Colin. Reviewers for the School Library Journal described Gleitzman’s pacing in the audiobook as “wonderful”, showing Colin’s growing maturity.

Stephens regards Two Weeks with the Queen as being unusual in contemporary Australian children’s literature because Colin is presented as having agency – he is capable of making decisions and taking action to change the world around him – even though he does not do so in the way he first intended. Maya Sen, writing for The Canberra Times, praises Colin’s determination and character development, and enjoyed the book’s humour and direct treatment of its themes.

When the play was performed in the United Kingdom, according to Gleitzman, the Australian Republican themes of the play proved controversial.