Nearly one in four of England's top-paid academy leaders received pay increases of 10% or more last year, figures suggest.
On average, the highest earners at 121 academy trusts - which run chains of schools - earned almost £180,000 each in 2015/16, around a fifth more than the Prime Minister, according to an analysis by the Times Educational Supplement.
Former Ofsted chief Sir Michael Wilshaw warned that the Government needs to take action to ensure that taxpayers' money is well spent.
The TES investigation is based on an analysis of the salaries of the highest earners at 121 academy trusts which paid at least one employee over £150,000 a year in 2015/16.
It found that, on average, the best paid individuals took home £179,000 last year - 19% more than the £150,000 salary given to Theresa May.
Nearly a quarter (24%) of these 121 top-earners received salary hikes worth 10% or more in 2015/16, compared to the year before, the TES found.
Clive Neathey, chief executive of the Rosedale Hewens Academy Trust - which runs seven schools, had the largest percentage increase.
Figures submitted to Companies House show that he was paid between £205,000 and £210,000 in 2015/16, up from between £85,000 and £90,000 the year before - a 141% increase, the TES reported.
The year before that, in 2013/14, his salary was between £110,000 and £115,000.
Beverley Amos, chair of trustees at the Rosedale Hewens Academy Trust, said: "The fact of the matter is that Mr Neathey had previously made a decision, in the interests of the Trust, to effectively take a significant pay cut at a time when the Trust was expanding by commissioning a number of new provisions.
"In fact, during this period he worked pro bono on at least three capital projects in order to safely establish our new schools within the funding envelope.
"Therefore assuming that the uplift in his remuneration is a salary increase, and expressing it in percentage terms, is in this instance misleading and something that should be set in context. The Board is grateful for the opportunity to clarify this matter."
This increase was significantly higher than the others found by the TES.
The analysis also suggests of the 80 academy chains that gave data on pension contributions, around three in five (61%) increased the amount they paid into the pension funds of their highest earner.
Sir Michael told the TES: "Public money is not being well spent and the excesses that we're seeing in relation to salaries will bring down the whole programme unless the DfE gets a grip."
Sir Michael, who is strong supporter of the academies programme, did not call for a cap on salaries - but did suggest that there needs to be closer scrutiny of pay rises, the magazine reported.
A Department for Education spokesman said: "It is essential that we have the best people to lead our schools if we are to raise standards. The board of trustees must ensure that their decisions about levels of executive pay follow a robust evidence-based process and are reflective of the individual's role and responsibilities."