Thousands of shoppers descended on malls and town centres in search of a bargain in the traditional sales, soothing fears over a retail decline in the last year.
Bargain-hunters arrived outside Braehead shopping centre in Renfrewshire an hour before Next opened at 6am.
General manager Peter Beagley said: "The Boxing Day tradition of hitting the shops to grab a bargain or two is very much alive and well.
"The early birds were up and out to catch the best deals and shoppers were queuing up at 5am waiting for stores to open.
"Today is a big part of the festive season for lots of people and there was quite a bit of anticipation among those waiting for shop doors to open so they could bag a bargain."
There were similar scenes at Union Square in Aberdeen which has had some of its busiest ever shopping days this month, with 1.2 million people through the centre before Christmas.
General manager Ryan Manson said: "The centre has been exceptionally busy since doors opened this morning and we saw queues outside stores including Next, Zara, Hollister and New Look.
"Shoppers are out in large numbers suggesting that the in-store discounts and sales are generating lots of interest with those keen to get their hands on fashion bargains from big brands."
Princes Street in Edinburgh and Buchanan Street in Glasgow were also busy with shoppers, while a spokesman for East Kilbride shopping centre said it was having one of its busiest ever days.
The Overgate centre in Dundee also had a busy start with Next sales starting at 6am.
As well as the millions of shoppers across the UK hitting the high streets, even more are expected to be searching for bargains online.
The growth in smart phones and tablets has been identified as part of the reason for the internet shopping increase and over the last five years, Amazon's UK website said it had seen sales on Christmas Day increase by 263%.
The retailer is launching further offers today, which include clearance offers and "lightning deals" for a limited time and quantity of stock.