MSL is Publicis Groupe's public relations and integrated communications network. Publicis Groupe announced Diana Littman as CEO of MSL U.S. in November 2018, reporting to chairman and CEO Arthur Sadoun, and described MSL as having more than 3,100 people across more than 107 offices at that time. MSL's own site says Littman leads a U.S. team of more than 300 and chaired the PR Council in 2024.
Company Info
- Parent: Publicis Groupe; MSL sits inside Publicis Communications, one of the group's solutions hubs, per Publicis' 2018 release
- Size: More than 3,100 people across more than 107 offices worldwide, per Publicis Groupe in November 2018; MSL says its U.S. team numbers more than 300
- Leadership: Diana Littman, CEO of MSL U.S., reporting to Arthur Sadoun; Margaret Key, CEO for Asia-Pacific, Middle East and Africa, per MSL's site
- U.S. offices at the 2018 announcement: Atlanta, Boston, Chicago, Detroit, New York, Seattle and Washington, D.C.
- Practices: Corporate communications, consumer marketing, social purpose and sustainability, employee communications, crisis, technology, health, and food and beverage
- Clients named by MSL: Procter & Gamble, Lilly, Inspire Brands and J.M. Smucker, per its site
- Website: mslgroup.com
- Last verified: October 17, 2026, against Publicis Groupe's November 2018 release, O'Dwyer's and MSL's site; the global headcount and office figures are from 2018 and current leadership should be confirmed with the firm
Originally published September 2026. Updated October 17, 2026.
Who leads MSL U.S.?
Publicis Groupe announced Littman's appointment in November 2018, with the goal of elevating public relations, influence marketing and earned engagement within its integrated model, and she also joined the Publicis Groupe USA Executive Committee. O'Dwyer's said she replaced Ron Guirguis and came from Marina Maher Communications, where she spent roughly a decade, after about a decade at Cohn & Wolfe. MSL's site says she started at MSL at the start of 2019 and was named to the PRWeek Power List in 2019 and 2020.
What does MSL do?
Publicis described MSL's capabilities as corporate communications, consumer marketing, social purpose and sustainability, employee communications, crisis, technology, health, and food and beverage. It called MSL one of the world's largest PR networks, one of the largest in Europe and the fastest growing in Asia-Pacific, which are Publicis' own descriptions.
Which clients does MSL serve?
MSL's U.S. page names Procter & Gamble, GM, Lilly, Inspire Brands and J.M. Smucker. PRWeek reported in 2019 that Cadillac named MSL its PR agency of record and that MSL added Swiffer and Mr. Clean to its P&G portfolio.
How does MSL compare with other global PR networks?
MSL competes with other holding-company networks and independents, including Edelman, Ogilvy PR, Burson, FleishmanHillard, Golin Ketchum and Havas Red. EPR's PR industry map shows how the holding companies fit together.
Related: PR agency profiles, PR industry map, PR leaders, Kekst CNC, 5W Public Relations
