The omission follows media reports that Trump no longer wants to come because of British public opposition to the visit, after a petition to cancel it received more than 1.8 million signatures.
It is customary for the monarch to list state visits in the annual speech, and Elizabeth did mention one such visit coming up next month by Spain's King Felipe and Queen Letizia.
British press reports after the speech said the visit was clearly now in jeopardy, but a spokesman for May insisted the invitation had not been revoked.
"The visit wasn't mentioned in the Queen's Speech because a date hasn't been fixed yet," the spokesman said.
Prince Philip had been due to accompany the monarch to the state opening of parliament on Wednesday as well as day two of the Royal Ascot horse races, but he was taken to hospital as a "precautionary measure" for treatment of an infection.
Their eldest son Prince Charles, the heir to the throne, accompanied Queen Elizabeth to the Houses of Parliament in his place.
Brexit draft laws presented
Prime Minister Theresa May on Wednesday presented eight draft laws to take Britain out of the European Union in a legislative programme read out in parliament by Queen Elizabeth II.
The laws include the "Great Repeal Bill" to overhaul existing EU legislation and separate bills on customs, trade, immigration, fisheries and agriculture.
The queen said the "Great Repeal Bill" would repeal the European Communities Act, the 1972 legislation that enshrined Britain's membership of the European bloc.
"My government's priority is to secure the best possible deal as the country leaves the European Union," the queen said in the speech.
She said her government would seek "to build the widest possible consensus on the country's future outside the European Union", amid divisions within her own cabinet over the best strategy.
Britain voted to leave the European Union in a referendum last year but there is growing opposition to the government's "hard Brexit" approach of cutting immigration at the expense of trade ties.
Queen's hat raises eyebrows
Queen Elizabeth II's choice of headgear for a speech setting out how the government will implement Brexit raised more than a few eyebrows on Wednesday, causing some to draw comparisons to the European Union's flag.
Twitter users posted pictures of the queen's blue hat decorated with flowers with yellow centres alongside an image of the blue flag of the EU, with the yellow stars representing its member states.
"Clearly the EU still inspires some in the UK," tweeted Guy Verhofstadt, the European Parliament's Brexit spokesman, while opposition Labour MP Paul Flynn jokingly referred to it as an "anti-Brexit hat".
Others quipped that the queen might be "trolling" May, pointing out that the 91-year-old British monarch might have been put out by having to attend the delayed formal opening of parliament instead of attending her beloved Royal Ascot horse races.
"Queen trolls Brexiteers," said one Twitter user, while another wrote: "The award for 'Best Trolling Using a Hat' goes to the #QueensSpeech".
"Is the queen trying to tell us something about Brexit with her hat?" the Daily Telegraph asked.
But others expressed confusion, given the rumours that the queen is in fact in favour of leaving the EU.
The BBC has reported that the queen said at a private lunch before the referendum that Britain should "just get on with" leaving the European Union and that Brexit would not be a "problem".
"Given the Queen's compulsory nonpartisan role in the Brexit negotiations, the hat remains riddled with ambiguity," the Guardian newspaper wrote.
"As to whether today will be known as the day she sidestepped impartiality to make a silent protest with her hat, we'll probably never know. But we can have fun with some memes".
