His role as Chancellor will be taken by Chief Secretary to the Treasury Rishi Sunak, MP for Richmond (Yorks).
Mr Javid, who had been Chancellor since last July, is believed to have refused to sack his aides in a clash with No. 10, according to media reports.
Prime Minister Boris Johnson has been carrying out a major Cabinet reshuffle today which has seen a large number ministers resign or be sacked.
In previous comments on his Budget plans, Mr Javid said that he planned to “unleash Britain’s potential.”
There have been concerns in the financial services sector that Mr Javid was planning to scale back pension tax relief to pay for an ambitious investment programme to “level up” Britain.
The FTSE fell on the news and was down 1.6% by 12.15pm.
Rachael Griffin, tax and Financial Planning expert at Quilter, said: "This was supposed to be a low-key reshuffle but instead we have yet another key ministerial change. It is really not a good look for the Chancellor to quit less than a month before their first Budget, and it leaves a host of issues hanging in the balance."
"It is yet to be seen whether Sunak will serve as No. 10’s puppet, given the speculation that the Prime Minister’s office is seeking to take closer control of the Treasury. He will inherit several political hot potatoes. For instance the government has already promised to fix its disastrous pension annual allowance taper, which has led to staffing shortages in key public services, including the NHS."
Mr Sunak lives near the North Yorkshire town of Northallerton. His father was a GP and his mother ran the chemist shop. He studied at Winchester College, Oxford University and Stanford University and was first elected to Parliament in 2015.
He worked in business for a number of years, co-founding an investment firm, working with companies from "Silicon Valley to Bangalore."
• This breaking story will be updated as further developments occur. Please check back later.