Florida Trend ranks the top 20 firms by revenue:

Ballard Partners
 (Jacksonville, Miami, Orlando, Tallahassee, Tampa Bay, West Palm Beach)
 Revenue: More than $8 million
 Lobbyists: Brian Ballard, Tony Boselli, Carol Bracy, Mathew Forrest, John Johnston, Sylvester Lukis, Joseph McCann, Bridget Nocco, Greg Turbeville, Amy Young, Chris Dorworth, Jan Gorrie
 Clients Include: Amazon.com, Automated Healthcare Solutions, Bayfront 2011 Development/Genting, City of Boca Raton, Florida Power & Light, Florida Virtual School, Fortress Investment Group, G.L. Homes of Florida, GEO Care, Harris Corp., New York Yankees, Tampa General Hospital, United States Sugar, Verizon
 
Southern Strategy Group
(Miami, Orlando, Tallahassee, Tampa Bay)
 Revenue: More than $8 million
Lobbyists: Paul Bradshaw, Oscar Anderson, Thomas Arnold, Laura Boehmer, David Browning, Electra Bustle, Christopher Dudley, Towson Fraser, Sofia Holtzman, James H. McFaddin III, Paul Mitchell, Lindsey Perkins, R.Z. “Sandy” Safley, Alex Setzer, Jim Smith, Stacey Webb
Clients Include: Amtrak, Apple, Florida Chamber of Commerce, IBM, International Speedway, Miccosukee Tribe of Indians, TECO Energy, US Airways Group, Walt Disney World, Wells Fargo
 
Ronald L. Book
 (Aventura, Tallahassee)
 Revenue: More than $5 million
 Lobbyists: Ronald Book, Rana Brown, Kelly Mallette
 Clients Include: Ashbritt, AutoNation, City of Tallahassee,
Florida Apartment Association, Florida Distillers, Florida Power & Light, GEO Group, Jackson Memorial Hospital, Miami Dolphins/Sun Life Stadium, Miami-Dade County, North and South Broward Hospital District, TEVA Pharmaceuticals, University of Miami, West Flagler Kennel Club/Magic City Casino

Full list here