The collective, said to be the largest ever to write to European Union competition chiefs, is urging tougher action by antitrust enforcers.
In a joint letter to EU competition chief Margrethe Vestager on Thursday (Nov 12) they said the U.S. tech giant unfairly favours its own services on web searches.
The group includes U.S. and UK companies, as well as peers in 21 EU countries.
They accuse Google of giving its services, such as those for accommodation, travel and jobs, preferential placement in its search results.
Google, a unit of Alphabet, has refuted the assertations.
It says that its users are not locked in and that competition to its services is just one click away.
Vestager has levied fines of $9.7 billion against Google over the past three years, for abusing its market power.
Signatories to the letter, seen by Reuters, included longstanding Google critics Yelp, Expedia and Trivago.
The group says new EU tech rules dubbed the Digital Markets Act will take too long to come into effect.
They urged Vestager to act swiftly to ensure Google gave its rivals equal treatment in search results.