Penicillin is a group of antibiotic medicines.

Penicillin may also refer to:

• Penicillin (band), a Japanese visual kei/alternative rock band
• Penicillin (cocktail), a cocktail based on whiskey, ginger, and lemon
• Penicillin (counter-artillery system), a Russian military sensor system
• "Penicillin (It Doesn't Mean Much)", a song by The Velvet Teen from Elysium, 2004