- law of rational indice
- law of rational indices
- law of reaction
- law of reciprocity
- law of rectilinear propagation
- law of reductio ad absurdum
- law of reflection
- law of refraction
- Law of Regarding the Strengthening of Ties Between School and Life and the Further Development of the USSR Public Education System
- Law of Regulations of Important Industries
- law of resistance
- law of retail trade gravitation
- law of securities regulation
- law of segregation
- law of series
- law of similarity
- law of similarity transformation
- law of similitude
- law of simplification
- law of sines
- law of sines for spherical triangle
- law of small numbers
- law of social development
- law of social security
- law of stream number