"You're carrying a gun to class? Yeah well I'm carrying a HUGE DILDO," Jessica Jin, organiser of Campus (DILDO) Carry, wrote on Facebook.
About 3,000 people have signed up for the protest, which is planned for next year when the law takes effect.
Gun rights supporters have criticised the rally on the group's Facebook page.
Texas Governor Greg Abbott enacted the campus carry law in June. Under the law, university presidents are permitted to create so-called "gun-free zones".
"The State of Texas has decided that it is not at all obnoxious to allow deadly concealed weapons in classrooms, however it DOES have strict rules about free sexual expression, to protect your innocence," wrote Ms Jin, a student at the University of Texas at Austin.
"You would receive a citation for taking a DILDO to class before you would get in trouble for taking a gun to class. Heaven forbid the penis," she added.
Some students at the Austin university have appealed to University President Gregory Fenves to impose limits on the new law.
Daniel Hamermesh, an economics professor at the university, said last week he was resigning over concerns about his personal safety.
Supporters of gun rights have argued that mass gunmen target "gun-free zones" such as university campuses and cinemas so they do not meet resistance when they commit their crimes.
Others say encouraging armed civilians to engage an attacker could lead to more chaos and deaths.
A student was armed during a recent college shooting in Roseburg, Oregon, but he did not use his weapon.
He was not in the building where the shootings occurred, and he also said he feared police could have mistaken him for the gunman, putting his life in danger.
Gun rights supporters have flooded the protest's Facebook page, mocking the organisers.
"A grand example of the decline of value in American university education," read one of the responses.
"As a parent I feel more comfortable with my children having a weapon on campus rather than a dildo," read another.
Texas students are planning to hang sex toys from their bags in protest at a law allowing people to carry concealed weapons on university campuses.