In both years, Police Scotland staff who earn more than £80,000 a year will see a flat-rate increase of £1,600.
Both years will also see a matching percentage increase on enhanced shift rates.
The deal runs to the end of March 2021 and was agreed by members in an online ballot that saw a 96.7% vote in favour on a 67.7% turnout by affected UNISON members.
UNISON police staff Scotland branch secretary Michelle Brewer pointed out that the lowest rate on the Scottish Police Authority pay scale will be £19,221 a year for a full-time job.
This is comfortably above the 2019-20 Scottish living wage rate of £17,385 a year.