This will be the first time since 1963 that the Queen will have missed this constitutional ceremony, which sets out the government's legislative plans.
Prince Charles will deliver the speech on Tuesday for the Queen.
The 96-year-old monarch has mobility problems and has had to cancel a number of recent public appearances.
Until Monday evening Buckingham Palace had been saying the Queen hoped to attend, but has now confirmed she will not go the ceremony in Westminster, because of "episodic mobility problems".
