The Chief Legal Ombudsman has told lawyers they need to do a better job in explaining their costs and pricing system to customers.
Adam Sampson said around one in four people contacting the legal complaint service does so to bring up the issue of fees.
In a report, he called on legal professionals to be more open and honest about their "confusing" costs and issued separate guidance for consumers and lawyers in an effort to tackle the problem.
The ombudsman said lawyers should clearly explain charges to customers as soon as possible and give a "reasonable estimate" of the total costs of a case.
Mr Sampson said the "key issue" when people use lawyers is confusion.
Speaking on BBC Breakfast, he said: "Simply put, when you go to lawyer at an important time of your life, a lawyer very often talks lawyer at you and doesn't make it really crisp and clear what they are going to do for you and what the price is going to be at the end.
"And that ends up in huge confusion. Many of the complaints we see, actually the lawyer hasn't overcharged, it's simply that the customer hasn't understood what the nature of the bill is going to be."
He said clients also often do not understand how much they will be charged.
"You can go to one lawyer who will give you a fixed price for what it is that they're going to do for you. You go to another lawyer and the lawyer will say 'No, my charge out is an hourly rate of £201 an hour plus VAT, plus disbursements' - again words that we don't understand and that doesn't give you any clarity about what your total bill is going to be."
Speaking of the importance of the legal ombudsmen, he added: "It's really vital that people do have somewhere independent to go. And in many cases, as I've said, when you look into it, in fact the lawyer's done nothing wrong, but in a significant number of cases there is a real issue here and fortunately we have the power not just to investigate but to order the lawyer to put it right."