J.W. Clark may refer to:

• James West Clark (1779–1843), a United States Representative from North Carolina
• James Waddey Clark (b. 1877), a Justice of the Oklahoma Supreme Court
• John Willis Clark (1833–1910), English academic and antiquarian
• John W. Clark (architect), American architect
• Joseph Walter "Joe" Clark (1890-1960), an English professional footballer

• PFF WL
• PFFWL
• PFF Women's League
• PFI Decision
• PFI Directive
• Pfieffe
• Pfieffe, Spangenberg
• P fimbriae
• Pfingstberg (Potsdam)
• Pfingsten, Minnesota
• Pfingstner
• Pfisterer Group
• Pfitzer (surname)
• Pfitzner, Alexander
• @pfizer
• Pfizer Animal Health
• Pfizer, Charles
• Pfizer Forum
• Pfizer litigation
• Pfizers
• PFK Dobrudzha Dobrich
• PFK Neftçi-2
• PFK Sementchi
• PFL 1
• PFL 10