The trip, aimed at cementing the strong relations between London and its oil-rich Gulf ally, kicked off with a traditional display of ceremonial pomp in Windsor, west of London.
Prince Charles, the heir to the throne, accompanied Sheikh Sabah al-Ahmad al-Sabah to the town, where he was met by Queen Elizabeth and her husband Prince Philip before a glittering state procession and a guard of honor.
It is the first state visit from Kuwait to Britain since 1995.
On Wednesday, the emir was to have a private audience with Charles, attend a meeting with British industry leaders hosted by the queen's second son Prince Andrew and hold talks with Prime Minister David Cameron.
Sheikh Sabah is accompanied on the trip by his finance, foreign and commerce ministers.