Peter Irvine, author of travel bible Scotland the Best, said parts of the World Heritage Site such as the Royal Mile were now “impassable” during peak periods.
And the former music promoter said some neighbourhoods in the city centre were being “spoiled” to the growing number of properties being let out for short breaks.
Mr Irvine, whose 25th anniversary edition of Scotland the Best is published this week, drew a comparison between Edinburgh and other cities in Europe which he said had become so “mobbed with people” that their historic atmosphere had been lost.
Mr Irvine’s comments echo warnings issued two years ago by the Edinburgh World Heritage trust that the city needed to take steps to ensure it “avoided the same fate as Venice.”
At the time, the body said there was a need for a collective effort to “understand the capacity limits of our fragile, historic city” and warned that “commercial exploitation” of the city’s historic environment was threatening its authenticity.
Controversy over its intervention was reignited last Christmas when the chair of the city’s main marketing body accused critics of the growth of the tourism industry of wanting the city “preserved in aspic”.
Mr Irvine said: “Over-tourism is a word that has only recently been coined, but those of us who live with it know what over-tourism means. If you live in Venice or other European city centres, including Edinburgh, then you know that tourists come in waves.
“In Edinburgh’s case, they come to the Royal Mile and sometimes make it impassable. You dread going across town if you have to go that way.
“If you go to an art gallery and they have a blockbuster exhibition on you know it is going to be crowded but your experience of the work is actually constricted.
“If you’re in the streets of Venice or up and down the closes of the Old Town of Edinburgh, and they’re mobbed with people, it’s pretty hard to get the atmosphere of that place, which is a medieval town.
“Scotland is booming with tourism at the moment. Edinburgh is at the front end of that, it’s the gateway. Most tourists who come to Scotland come to and through Edinburgh.
“We’re going to have more and more tourists. They’ll want more and more things to do. A lot of tourists travel in groups and go to exactly the same places at exactly the same time.”
Mr Irvine also called for a clampdown on controversial rental site Airbnb, claiming it was “almost out of control” in Edinburgh.
The city council is lobbying the Scottish Government for the powers to insist that a 45-day limit is imposed on property owners using Airbnb. However, the firm wants hosts to be able to rent out their properties for 90 days in addition to the winter and summer festival periods.
Mr Irvine added: “The whole thing is a conundrum in Edinburgh. It probably has more hotels opening than anywhere else in Britain, although the hotel sector is already well served, particularly at the top end, and Airbnb has gone through the roof. There are lots of us in Edinburgh who think it should be seriously controlled.
“It needs taken in hand very soon. There are some properties in the city centre which are mostly Airbnb now. It’s spoiling residential neighbourhoods. There have to be limits put in place on how often you can rent somewhere out.”
Mr Irvine said he had experienced overtourism in several other parts of the country, including the Outer Hebrides, Orkney and around the route of the North Coast 500 while researching his new book.
He said soaring demand for accommodation in some rural areas had effectively extended the traditional summer peak to a six-month long season between April and September.
Mr Irvine, who was previously honoured by VisitScotland for services to Scottish tourism, urged the body to lead a rethink of marketing strategies to focus on areas which were still largely ignored by tourists, including the Borders and Dumfries & Galloway.
He said: “The phenomenon of over-tourism means that tourist seasons are now extending. It’s no longer just a few months in the summer. We famously don’t have great weather in Scotland, but independent travellers don’t care – if they like the landscape they come dressed for the weather.
“Most people I know don’t go around Scotland in the summer, they go in the spring or autumn, but they are both also very busy now. I saw over-tourism myself in certain places, particularly in the islands, and I went in March and April. It was hard even then to get a hotel room and I could see how busy they were for the rest of the year.
“This isn’t just about Skye. Islands like Coll, Tiree and Eigg are finite.
“The North Coast 500 campaign has been an amazingly successful marketing campaign, but the downside is getting somewhere to stay. There just aren’t that many hotels up there.”