The single-crystal elastic constants Cij of β-cubic PbF2 (fluorite type) have been measured to ~0.3 GPa at ambient temperature and to 573 K at ambient pressure. The measured Cij are (in gigapascals (GPA)): C11=96.075¿0.094, Cs =(C11-C12)/2 =24.475¿0.018, and C44=20.835¿0.012. The results from the least squares linear fit of the pressure data to ~0.3 GPa yield dC11/dP =7.79¿0.08, dCs/dP =0.21¿0.08, and dC44/dP =0.82¿0.02, and the temperature data in the range of 298-373 K give (in GPa per degree ¿102): dC11/dT =-5.63¿0.05, dCs/dP =-1.26¿0.03, and dC44/dT =-1.11¿0.07. The pressure derivatives do not give any indication of the monotropic transition at ≤0.4 GPa; likewise, the temperature derivatives do not indicate the onset of superionicity at high temperatures. Relative stability of the α, β, and β' phases of PbF2 is discussed in light of thermodynamic parameters.