TTC’s 18 brands include Trafalgar, Uniworld Boutique River Cruises, Contiki and Insight Vacations.
TTC chair Brett Tollman said: "For more than 104 years, our family has built TTC into an industry leader known for exceptional service and innovation.
"Without a next generation to lead TTC, the time has come in our strategic succession plan to select a new owner with a proven track record and who shares in our vision and customer-first values.