- Original Penguin
- Onitsuka Tiger
- Oakley
- O’Neill
- Oui
- Oilily
- Osprey
- Obey
- Only
- Osiris
- Ogio
- One Seven Two
- One
- Osklen
- O.X.S.
- Opening Ceremony
- Odd Molly
- Original Vintage Style
- Orlebar Brown
- Oregon Scientific
- Oscar De La Renta
- Onyx
- Oakwood
- Octopus
- Object
- Officina 36
- Ortigni
- Omega
- Olla Parèg
- Oliver Goldsmith
- Ontour
- Oscalito
- Odeeh
- Our Legacy
- Orciani
- Orion London
- Ovye By Cristina Lucchi
- Oasis
- One Teaspoon
- Opililai
- Odlo
- Oliver Spencer
- Orwell
- Oliver Peoples
- Officine Creative
- Olivia Rubin
- OAS
- O Jour
- Orelia
- Only Play
- Ortovox
- Olympia Le-Tan
- Oscar Jacobson
- Olow
- Oryany
- Olang
- Orient
- ottod´Ame
- Osman
- One Way
- Olga Berg
- Oaks
- On And On
- Osey
- Onia
- Oroscuro
- Oxydo
- Odi Et Amo
- Olivia Burton
- Operasei
- Olivia Von Halle
- on parle de vous
- Oris
- Officine Generale
- Olivieri
- Odieuses
- Ovadia & Sons
- OVERCOME
- Office
- Obaku
- Off-white
- Options
- O’ Dan Li
- On Running
- Oceanaut
- Onzie
- O6 Milano
- Otto Kessler
- Only & Sons
- Ocean Republic
- OAMC
- Olivia Hops
- Ouigal
- Opaline
- OFF
- OLIVIA NICOLAI
- Only Petite
- Outerknown
- OBVIOUS BASIC
- Ocra
- Olympia Activewear
- Olgana Paris
- Oscar Tiye
- OSKA
- O bag
- ONCE MILANO
- Ones
- Opinion Ciatti
- Oyuna
- Oji
- of Handmade
- Orian
- Oasi
- OUTSUNNY
- Octo
- Outfit Italy
- Olvi’s
- Ottolinger
- Osanna Madina Visconti di Modrone
- Omc
- Onedress Onelove
- ONE by Oneteaspoon X
- OOF
- Oscar Valentino
- Ouvert Dimanche
- OpenClosedShoes
- Oficina Lozoya
- O.D.D. Objets de Desir
- Operà
- Olivier Theyskens
- Onako
- Otto Asole
- Organik
- Ocean Star
- Olga Rubini
- Orslow
- Olaf Hussein
- Officina del Poggio
- Osvaldo Rossi
- Olivia Gold
- OW Intimates
- Outrageous Fortune
- Ottaviani
- Olivia’s Bow
- Only Play Plus
- Oséree
- Only Carmakoma
- Ookonn
- Organic Basics
- Oh Baby!
- Old England Paris
- OSSIANI
- Outrageous Fortune Plus
- Odyssee
- Outhere
- Only Tall
- Overlord
- Over-D
- Opificio Neirami
- Ordi.to accessori
- Our Fly
- O Mai
- Odì Odì
- Opificio Milano M
- Our Flag
- Ochi
- OH! MY SANDALS
- Ooak
- One 0
- One & Other
- Origami Lab
- OOF Wear
- Oltre Tempo
- Opsobjects
- Original Grade
- Ororo
- ottod’Ame
- Object Particolare Milano
- Overlover
- Oud Paris
- Olivia Palermo
- OKLYN
- Onyx Collective
- OA Non-Fashion
- Otro Amor Bikini
- Oui & Me
- Original Madras Trading Company
- Overlapping
- Open Lab
- Olenich
- Off the Pitch
- OFF PLAY
- Olive e Miele
- OAK25
- OZAIA
- OW Collection
- OE Shoes
- Officine Del Golfo