H40 may refer to :

• H-40 (Michigan county highway)
• H-40 a sailing yacht designed by Hans Groop
• HMS H40, a Royal Navy ship name
• Hoffmann H-40, a 1988 German prototype sports plane
• HMS Anthony (H40), destroyer

and also :

• Glaucoma ICD-10 code
• Londonderry vice-county code

• Traffic signs in Pakistan
• Traffic signs in the United Kingdom
• Traffic signs in the United States
• Traffic Stop
• Traffic Stop (film)
• Traffic street
• Traffic Street Records
• Traffic street records
• Traffic suppression
• Traffic system
• Traffic Troubles
• Traffik
• Traffik (2018 film)
• Trafford Bar Metrolink station
• Trafford Centre Metrolink station
• Trafford council
• Trafford Council election, 2018
• Trafford (family name)
• Trafford Housing Trust
• Trafford (last name)
• Trafford Mausoleum, Wroxham
• Trafford MBC
• Trafford Metropolitan Borough
• Trafford Metropolitan Borough Council election, 1973
• Trafford Metropolitan Borough Council election, 1975