The 2009–10 Slovenian PrvaLiga was the 19th season of top-tier football in Slovenia.
Primorje were relegated to the Slovenian Second League after the last-place finish in 2008–09, thus ending their sixteen-year spell in Slovenia's highest division.
Drava Ptuj successfully avoided relegation for the second year in a row by beating Second League runners-up Aluminij in the relegation play-offs.
The ninth-placed team of the PrvaLiga, Interblock, played a two-legged relegation play-off against the runners-up of the 2009–10 Slovenian Second League, Triglav, for a spot in the 2010–11 PrvaLiga.
Every team plays four times against their opponents, twice at home and twice on the road, for a total of 36 matches.