RPN may refer to:

Science and technology

• Real projective space (${\displaystyle \mathbb {R} \mathrm {P} ^{n},}$), a type of topological space
• Reverse Polish notation, a.k.a. postfix notation, a mathematical notation
• Registered Parameter Number, in MIDI
• Recherche en Prévision Numérique, weather forecasting research service, Canada
• Risk priority number in failure analysis such as FMEA, taking into account the severity, probability and detection probability of a failure event

Media and culture

• Radio Philippines Network, Channel 9

Nursing

• Registered practical nurse, nursing title
• Registered psychiatric nurse, nursing title specialising mental health

Places

• Rosh Pina Airport (IATA code), Israel

Other uses

• Rancangan Perumahan Negara (National Housing Programme), public housing in Brunei