The EU’s executive said it expected Polish GDP to expand 4.1 percent in 2019 and 3.3 percent in 2020.
In July, the commission had predicted the Polish economy would grow 4.4 percent this year and 3.6 percent next year.
Although the Polish economy is expected to slow, the commission forecasts it will be among the fastest-growing in the European Union in 2020.
The commission predicts that only Malta (with 4.2 percent growth), Romania (3.6 percent) and Ireland (3.5 percent) will outperform Poland next year.
The Polish economy grew 4.5 percent in the second quarter of this year, the country’s Central Statistical Office (GUS) said in August in a final estimate.
The country’s central bank chief, Adam Glapiński, said in early October that the Polish economy was in "excellent" shape and on track to grow 4.3 percent in 2019.
Glapiński admitted last month that the Polish economy was set to lose some of its momentum amid a global slowdown, but added the country’s GDP growth would remain solid.