In her Budget response, Conservative leader Kemi Badenoch said Labour should rename itself "the Welfare Party", adding: "All this Budget delivers is higher taxes and out of control spending."
Badenoch said the Budget was a "total humiliation" for Reeves, who should "resign".
"Last year she put up taxes by £40bn, the biggest tax raid in British history," she said.
"She promised that she wouldn't be back for more. She swore it was a one-off. She told everyone that from now on it would be stability, and she would pay for everything with growth.
"Today she has broken every single one of those promises."
Liberal Democrat leader Sir Ed Davey said: "Labour was elected on a promise of tackling the cost of living crisis and growing the economy - and this is the second Budget where it's failed to do either.
"For millions of people struggling with higher bills, all this budget really offers is higher taxes."
Speaking at a news conference, Reform UK leader Nigel Farage said: "I would very much sum up this Budget as an assault on aspiration and an assault on saving."
He added: "Working people are going to be subsidising a welfare bill that shows no sign of going down whatsoever."
The Green Party said the Budget "papers over the cracks" instead of taxing "extreme wealth fairly".
"The chancellor spoke about asking everyone to make a contribution, but it is frankly inexcusable that she has made the political choice to squeeze households already struggling with the cost of essentials, whilst letting multimillionaires and billionaires off the hook," Green Party Treasury spokesman Adrian Ramsay said.
The SNP said the Budget "fails to deliver" for Scotland.
Shona Robison said the Budget was "a chaotic mess" that failed to back Scottish jobs - and the announced funding £820m uplift would "not even cover half the cost of the employers' national insurance contributions brought in this year."
Government borrowing costs eased back and the pound strengthened after an initial sell-off sparked by the early release of the OBR forecasts.
But the Institute for Fiscal Studies think tank said the increase in "headroom" in the Budget forecasts relied on tax increases just before the next general election, which it said should be "treated with a healthy dose of scepticism".