AbstractBased on in situ measurements by Wind spacecraft from 2005 to 2015, this letter reports for the first time a clearly scale‐dependent connection between proton temperatures and the turbulence in the solar wind. A statistical analysis of proton‐scale turbulence shows that increasing helicity magnitudes correspond to steeper magnetic energy spectra. In particular, there exists a positive power law correlation (with a slope ∼0.4) between the proton perpendicular temperature and the turbulent magnetic energy at scales , with k being the wave number and ρp being the proton gyroradius. These findings present evidence of solar wind heating by the proton‐scale turbulence. They also provide insight and observational constraint on the physics of turbulent dissipation in the solar wind.