The appointment is part of a restructure in which Olivia Dunn takes up the top UK marketing role.
Moll, currently head of Honda's UK marketing department, will assume the role of head of marketing communications and will take up the post on October 22.
Armstrong left Honda in January to join Jaguar in a global marketing role.
Moll, who has been with Honda for 17 years, has been head of the company's UK marketing department since April 2010.
Honda said that Moll "will be pivotal in developing a coordinated European marketing strategy, based around the need for a consistent and clear Honda brand image across the region.
Moll said: "It's an exciting time for me to join the European business and with the announcements of some key products, it presents a great opportunity for us to reinforce the brand qualities and strengths with consumers in the 27 countries in the region."
Replacing Moll will be Olivia Dunn, who takes over the role of head of marketing for Honda UK, also on October 22.
Dunn has been with Honda for 11 years, has been responsible for delivering a range of product launches and tactical campaigns.Follow @johnreynolds10