The Hang Seng Index had opened the day 17 points higher, after Wall Street edged higher overnight as traders were buoyed by healthy earnings results.
But the local benchmark was unable to hold on to those early gains, dipping 500 points before closing the day down 401 points, or 1.5 percent, at 27,321.
Market turnover was HK$139.6 billion.
For the week, local stocks were down 2.4 percent.
Education stocks took a hit amid rumours that mainland authorities will tighten control over such organisations.
New Oriental, which plunged by 40 percent, triggered the five-minute cooling-off period six times due to price volatility. Koolearn Tech and Scholar Education each plummeted for over 28 percent.
Tech plays also took a beating, with Kuaishou losing around 11 percent.
The worst blue-chip performer was Haidilao Hotpot which shed 5 percent.
Shijiazhuang Pharma Group, meanwhile, bucked the trend and gained 2 percent.
Elsewhere, the Shanghai Composite Index fell 0.7 percent, while the Shenzhen Composite slipped 1.4 percent.
Taiwan stocks were up marginally.
Tokyo gained 0.6 percent, Seoul and Sydney edged higher, while Singapore was down marginally.