Queen Elizabeth II has not visited every country in the Commonwealth. The Commonwealth is a diverse association of 54 member countries, and it would be a significant undertaking for any individual, including the Queen, to visit each one.
However, Queen Elizabeth II has made numerous visits to many Commonwealth countries during her reign, prioritizing those with closer historical ties and regular interactions with the United Kingdom. She has undertaken over 200 official visits to Commonwealth countries, attending Commonwealth Heads of Government Meetings (CHOGM) and other significant events. These visits have helped foster relationships, promote goodwill, and strengthen diplomatic ties within the Commonwealth.
It's important to note that the Queen's travel schedule and priorities are determined by various factors, including the significance of events, diplomatic considerations, and her health. Therefore, while she has made significant efforts to engage with Commonwealth nations, it is unlikely that she has visited every single country within the Commonwealth during her long reign.