BaMoO₄:Pr³⁺ phosphors have huge promise as a red emitting component for white LEDs. Here, we report small-size, monodispersed BaMoO₄:Pr³⁺ nanocrystals prepared by an effective liquid–solid–solution (LSS) method. These NCs exhibit narrow-linewidth luminescence emission with ultrahigh color purity for red, which is a perfect combination of both nanoparticles and luminescent properties.