FR4 may refer to:

• FR-4 or FR4, a NEMA grade designation for glass-reinforced epoxy laminate material
• The Magister, the fourth supplement of the Forgotten Realms series role-playing game
• France 4, a television channel in France

• Kelvin Moore (baseball)
• Kelvin Moore (footballer) (disambiguation)
• Kelvin Morris
• Kelvin Norman
• Kelvin Ogilvie
• Kelvin Onosiughe
• Kelvin O'Shea
• Kelvin Pope
• Kelvin Power Station
• Kelvin probe
• Kelvin Probe
• Kelvin problem
• Kelvin Road School
• Kelvin Robertson
• Kelvin Robin Tremain
• Kelvin Seamount
• Kelvin Sebwe
• Kelvin Sheppard
• Kelvinside Hillhead Parish Church
• Kelvinside Hillhead Parish Church, Glasgow
• Kelvin Skerrett
• Kelvin Snoeks
• Kelvin Stevenson Memorial Church
• Kelvin structure
• Kelvin Tan Wei Lian