Sage Pay was a payments processing service owned by The Sage Group plc between 2006 and 2020. It operated in the UK, Ireland, Germany, Spain, South Africa and the United States. The company provided online payments processing as well as products for face-to-face and telephone payments.

The UK and Ireland business was acquired by U.S. Bancorp's UK arm of Elavon in 2020 and was initially rebranded as Opayo, before taking on the group's Elavon branding.

The Opayo business was founded in 2001 as Protx, a business that processes online payments for small and medium sized businesses. Sage Group purchased Protx for £20 million in 2006. Protx had 10,000 customers in 2006. Protx was rebranded as Sage Pay in April 2009. Sage Pay entered the Irish market and opened a customer service centre in Newcastle upon Tyne during the same year.

As of 2019^[update] Sage Pay had 300 employees and serves 50,000 customers.

In February 2012, Sage Pay entered the card machine payment market when they acquired Integral Computers Ltd for €20 million. Integral Computers was founded in 1989 and its point of sale technology was used in 25,000 locations in 2012 across the UK and Ireland.

In 2019, Sage Pay and Worldpay, Inc. announced they were to partner to provide additional services in the UK and Ireland.

In November 2019, Elavon announced the acquisition of the UK and Irish Sage Pay business for £232 million. The Sage Salary and Supplier Payments portion of Sage Payments was not included in the deal with Elavon. The sale was completed on 11 March 2020 and the business was rebranded as Opayo in July of the same year. By 2024 the Opayo brand had fallen out of use with the business simply operating under the wider group's Elavon brand name.

Sage Pay launched in Germany in October 2012 and in Spain in September 2013. Sage Pay is no longer listed on the German and Spanish Sage websites.