Bletchley Park was awarded runner-up status in the Group Leisure Awards 2015.
The awards, which are run by industry magazine, Group Leisure, also featured the Warner Brothers Studio Tour - The Making of Harry Potter, The View from The Shard and Warwick Castle.
Portsmouth Historic Dockyard was crowned the winner.
Kelsey Griffin, Bletchley Park’s Director of Marketing and Communication, said: “It is wonderful that our museum has been highlighted as a top visitor attraction for groups.
“More people are visiting Bletchley Park each year - we have had more than 250,000 visitors already in 2015 - and many of those people have come as part of an organised group outing.
“Earlier this year we were named Best Attraction For Groups in the 2015 UK Group Travel Awards, and this latest accolade is further proof, if it were needed, that Bletchley Park is a great day out for groups.”
So far this year, more than 1,300 groups have visited Bletchley Park. Once Britain’s best kept secret, Bletchley Park is a combination of indoor and outdoor space, where history lives in the very walls of huts and blocks built in the 1940s for the 9,500 or so men and women who broke codes and ciphers, generating war-winning intelligence, amid complete secrecy.
Discounted tickets are offered to pre-booked groups of 12 or more. Bletchley Park is currently running a joint offer with Woburn Abbey.