The monarch, 96, reluctantly pulled out of the major ceremonial occasion as she continues to experience "episodic mobility problems" with royal doctors advising her against attending.
The Prince of Wales will read the Queen's Speech for the first time instead of Her Majesty, Buckingham Palace has announced.
The Duke of Cambridge, also a future monarch, will also attend the State Opening - the first time Prince William has done so. π
As Charles takes on the head of state's major constitutional duty for the first time, the move - believed to be unprecedented in modern history - will be interpreted as a significant shift in his responsibilities as a king in waiting. #PrinceCharles
Buckingham Palace said in a statement: "The Queen continues to experience episodic mobility problems, and in consultation with her doctors has reluctantly decided that she will not attend the State Opening of Parliament tomorrow."
The Queen is understood to have a busy diary at Windsor this week with a call with Australia undertaken on Monday, and a planned virtual Privy Council and phone audience with the Prime Minister on Wednesday.
She is also planning some private engagements π
It will be only the third time during her reign that the Queen has not opened parliament - and the first time nearly 60 years.
Here's a thread on Prince William paying an Oasis-inspired tribute to the victims and Manchester bombing bereaved π§΅
A new memorial has opened to the 22 people murdered in a terrorist attack after an Ariana Grande concert at Manchester Arena on May 22, 2017. #manchesterbombing
Prince William - the Duke of Cambridge - gave a deeply personal tribute to the still grieving loved ones of the 22 people murdered in the Manchester Arena terror bombing.
The trial, which has drawn attention globally, has mainly seen fans of actor Johnny Depp rush to his side in support of the alleged abuse he suffered whilst together with actress Amber Heard during their 15-month whirlwind marriage.
As Prince Charles delivers the Queen's speech to parliament today, royal commentators are saying Prince Charles is teetering on the edge of becoming a 'de facto prince regent'
The Queen is sending her 'Fantastic Five' to all corners of the UK for her Platinum Jubilee celebrations
Here's a thread on why, and who is going where 𧡠#PlatinumJubilee
The Queen will send senior royals all over the United Kingdom during her Platinum Jubilee double bank holiday weekend celebrations next month. #PlatinumJubilee π π¬π§
Scotland, Wales and Northern Ireland will have royal visits to ensure the Windsors spread the joy while many of the main events are taking place in London.