Justin Long as Adam

Cobie Smulders as Allison

Ryan Hansen as Aaron

John Cho as Mark

Kristen Schaal as Talula

Peter Gallagher as Orson Schwartzman

Dana Delany as Wendy (Allison's Mom)

Rick Overton as Dean (Allison's Dad)

Lea Thompson as Deb (Adam's Mom)

Brady Rubin as Grandma Rose

Luis Guzmán as Federico

Ginger Gonzaga as Helen

Charlyne Yi as Claire

Briga Heelan as Julie

Parvesh Cheena as Rohan

Malcolm Barrett as Greg

Dov Tiefenbach as David

Charlotte McKinney as Charlotte

Manu Intiraymi as Lee

Barbara Browne as Susan

André Tardieu as Jean-Pierre

Talia Toms as Leandra (Bridesmaid)

Adam Rose as Alan (Co-Worker)

Sam Hennings as Priest (Father Jack)

Ser'Darius Blain as Wedding DJ

Emerson Min as Emerson

Ivy George as Ivy (Flower Girl)

Babar Peerzada as Chaplin (Lead Busboy)

Gabriel Berber as Busboy 1

Victor Douglas as Busboy 2

Ricardo Martín as Wedding Photographer

James Krisel as Guy at Party

Vella Lovell as Jen (uncredited)

Andrea LeBlanc as Lindsay (uncredited)

Patrick Rafferty as Elevator Tourist (uncredited)

Mike Guerra as Engaged Couple (uncredited)

Ashley Platz as Engaged Couple (uncredited)