Her youngest son, Prince Edward's children, Lady Louise Windsor and James, Viscount of Severn, are also thought to be favourites of Her Majesty.
Meanwhile, Prince Andrew's daughters Princess Beatrice and Princess Eugenie are rarely mentioned.
Prince Harry is another favourite of the Queen, despite his decision to leave his royal role, and the pair are often photographed laughing and joking together at royal events.
In fact, during her recent statements about the royal exit, the Queen repeatedly expressed her love and support of Harry, offering unprecedented insight into how deeply she cares for him.
The grandchild who gets the least of Her Majesty's time, on a private level, is said to be Prince William.
As William has always been groomed for his future role as King, Queen Elizabeth is said to have both a personal and professional relationship with him.
The Queen has spent much of her life mentoring him for the day he will take the throne, the Duke of Cambridge has missed out on being labelled her favourite.
The mentoring has reportedly made the nature of their relationship much more serious than it is with her other grandchildren.