Sheila Rogers with "No Drilling Lethbridge" gave the petitions to the city's MLA, Greg Weadick, on Monday.
Rogers said the group had a massive response to its petition, which calls on the province to prohibit oil and gas drilling within the city.
GoldenKey Oil has secured mineral rights from Alberta Energy in an undeveloped area of southwest Lethbridge but has yet to apply to the Alberta Energy Regulator to drill three oil wells on privately owned land within city limits.
The proposed wells are classified as sour wells, as they would be drilled through a sour geological formation, but would produce from a non-sour zone.
Rogers says the company's mineral rights lease is set to expire and is up for renewal on March 24.
Note to readers: This is a corrected story. An earlier version said the petition had 11,00 signatures.