Police spokesman Kese Smith said Tuesday $200,000 in cash and $400,000 in checks were stolen from a safe sometime between 2:30 p.m. Sunday and 8:30 a.m. Monday.
The theft was reported Monday morning by a church employee and an off-duty sheriff's deputy who provides security at the facility.
No arrests have been made, Smith said.
Church officials declined to comment Tuesday.
In a statement issued Monday, Lakewood Church said the money and checks taken, as well as some envelopes with written credit card information, were limited to funds given during this past weekend's Saturday and Sunday services.
"We are working with the police to fully investigate the incident," the statement reads. "The funds were fully insured, and we are working with our insurance company to restore the stolen funds to the church."
The church encouraged people who made contributions this past weekend to keep track of their accounts and report any suspicious activity.
But church officials noted there was no electronic data breach and that individuals who put their offerings in a drop box, gave online or made a bookstore purchase were not affected.
More than 40,000 people attend weekly services led by Osteen, whose televised sermons reach nearly 100 countries.