Which star is hotter Regulus or Deneb?

Regulus is hotter than Deneb. Regulus is a blue-white main sequence star with a surface temperature of around 12,000 Kelvin, while Deneb is a blue supergiant star with a surface temperature of around 8,500 Kelvin. The color and temperature of a star are related to its size, age, and stage in its life cycle.