Officers from West Midlands Police shut down two parties in the Wednesfield area of Wolverhampton on Saturday night.
Fines of £1,000 were handed to both organisers of the events, as well as £200 fines for everyone else in attendance.
A spokesman for West Midlands Police said: "Wednesfield officers attended two incidents of Covid breaches last night [Saturday].
"Two house parties were shut down and the organisers now face a £1,000 fine, and everyone else present a £200 fine.
"There is no excuse to ignore the current Tier 3 rules."
Wolverhampton, along with the entire Black Country and the majority of the West Midlands, was placed into Tier 3 – Very High Alert area – when the Government introduced its updated tier system after the national lockdown ended earlier this month.
Under the regulations, people are banned from mixing indoors with anyone from other households – or in any private outdoor setting.