RPN may refer to:
Science and technology
- Real projective space (<math>\mathbb{R}\mathrm{P}^n,</math>), 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
Nursing
- Registered practical nurse, nursing title
- Registered psychiatric nurse, nursing title specialising mental health
Other uses
- Radio Philippines Network, a state-sequestered television network
- Rosh Pina Airport (IATA code), Israel
- (National Housing Programme), public housing in Brunei