Experian Marketing Services said 115.5 million visitors browsed the top retail Web sites on Dec. 25.
Overall, holiday shopping online was up 10 percent in 2012 compared to 2011, the market research firm said.
Amazon.com received the most traffic on Christmas Day with 24,657,838 visitors. Walmart was No. 2 on the list with 7,359,685 visitors.
The top 10 also included Target, BestBuy, Macy's, Sears, Fandango, Kohls.com, Apple Store and JC Penney.
The data suggest an increasing number of shoppers were treated to gift cards on Christmas Day.
Visa gift cards topped the list in online searches in the week ending Dec. 22, Experian said.
Among gift card searches, Visa was followed by iTunes, Amazon, Walmart, Starbucks, American Express, Vanilla, Redbox, Kroger and Mastercard.