Government statistician Samuel Kobina Annim said the third quarter growth figure - 2.9% - was the lowest since the economy expanded 3.1% in the first quarter of 2021.
"This is the least we've grown since the economy began to bounce back from the COVID-19 pandemic," Annim told reporters.
This year's third quarter growth was underpinned by the agricultural sector, where most growth came from fishing.
Industry saw the lowest growth, with its manufacturing sub-sector shrinking by 7.4% but mining expanding by 14.9%.
Ghana revised growth for the first quarter of this year to 3% and to 4.7% for the second quarter, down from 3.3% and 4.8% respectively, Annim added.
The West African country, experiencing its worst economic crisis in a generation, defaulted on most of its external debt on Monday.
Growth has slowed since a post-COVID pandemic recovery in 2021 as Ghana has grappled with runaway inflation, a depreciating local currency and spiraling debt.
The economic woes have been a central theme of street protests this year. In a bid to stabilize the economy, the government has negotiated a $3-billion staff-level agreement with the International Monetary Fund (IMF). Its approval is conditional on comprehensive debt restructuring.