Which? compared the prices, excluding tax, of 13 identical products ranging from televisions and gaming consoles to desktop applications and security software and found UK consumers are paying more than they would in the US.
The price difference of some items, calculated on June 18, ran to hundreds of pounds. The consumer group found a Samsung television was £402 more expensive in the UK, and an Apple MacBook Pro 13-inch laptop cost £194 more here than in the US.
The Microsoft Xbox One and the Sony PlayStation 4 were both £57 more expensive here.
UK shoppers are also paying "over the odds" on digital goods, with a 12-month subscription to the imaging software Adobe Creative Cloud costing £114 more here than in the US.
Which? advised consumers to consider buying digital products in-store as items such as Microsoft Office were sold by the company at a fixed price but physical versions were sold by numerous retailers and more likely to be discounted.
The watchdog has called on manufacturers to "play fair" and explain why technology products are more expensive in the UK.