Rubidium fluoride (RbF) is the fluoride salt of rubidium. It is a white crystalline solid with a cubic crystal structure, similar to common salt. It forms two different hydrates, a sesquihydrate with the stoichiometric composition 2RbF·3H₂O and a third hydrate with the composition 3RbF·H₂O.

There are several methods for synthesising rubidium fluoride. One involves reacting rubidium hydroxide with hydrofluoric acid:

Another method is to neutralize rubidium carbonate with hydrofluoric acid:

Another possible method is to react rubidium hydroxide with ammonium fluoride:

The least used method due to expense of rubidium metal is to react it directly with fluorine gas, as rubidium reacts violently with halogens:

The enthalpy of solution of rubidium fluoride was determined to be −24.28 kJ/mol.

Rubidium fluoride has a purple or magenta red flame test.

In addition to simple rubidium fluoride, an acidic rubidium fluoride with the molecular formula HRbF₂ is also known, which can be produced by reacting rubidium fluoride and hydrogen fluoride. The compounds H₂RbF₃ and H₃RbF₄ were also synthesized.