Allerton-Griffiths joins APT from Kuoni, where she held the same title, bringing 25 years' industry experience across sales leadership, team development and commercial.
In her newly created role with the river cruise and escorted touring specialist, she will be tasked with driving retail growth and deepening the group's partnerships with agents. She will lead APT's retail sales team, working closely with consortia, agency groups, independents and homeworkers.
Allerton-Griffiths will also have oversight for strategic partnerships, while her remit also includes increasing agent engagement and ensuring they are equipped to sell APT Luxury and Travelmarvel.
She started her career in travel with Thomas Cook and has spent the past more than 14 years with Kuoni, working her way up from a Personal Travel Expert role to National Retail Manager.
APT said Allerton-Griffiths' appointment underlined its commitment to the UK travel trade and follows "several years of double-digit growth".
Brad Bennetts, Head of Sales for APT Luxury and Travelmarvel, said: “The travel trade is at the heart of our business, and bringing Jemma on board reflects our commitment to the channel.
"Jemma really understands the retail market and what agents need from their supplier partners. She’ll bring fresh energy and commercial focus to our retail strategy and help us build even stronger relationships with agents."
Allerton-Griffiths added: "Both APT Luxury and Travelmarvel have fantastic offers and ambitious growth plans, and the commitment to working closely with travel agents is clear.
"My first priority is to get out into the market, meet our agents, and hear their views. I want to find out where we can offer more support and develop practical ideas that help our partners confidently recommend our products and grow their business with us."
APT is also recruiting for a Business Development Manager to look after agents in the south of England.