That's according to new data released Thursday by the U.S. Census Bureau.
The city added just over 3,900 residents between 2017 and 2018 for a total population of 1,584,138.
And while that continues the upward trend, the growth was a minuscule change of "1/4 of 1%."
At this rate, Philadelphia, which is currently the country's sixth largest city, could soon fall behind San Antonio, Texas, which is seeing rapid growth.
Only the city of Phoenix, Arizona saw a bigger influx last year.