Bertha Boronda (née Zettle; March 14, 1877 – January 18, 1950) was an American woman who sliced off her husband's penis in 1907.

She was convicted of the crime of mayhem; she used a straight razor to cut off her husband's penis.

[4] On Friday, May 30, 1907, Bertha insisted that her husband Frank had visited a place of prostitution.

[6] She was apprehended while disguised, wearing men's clothing and mounting a bicycle to make her escape.

[6] The felony of mayhem, punishable by up to 14 years in prison, was defined by Section 204 of the criminal code: "Every person who unlawfully and maliciously deprives a human being of a member of his body or renders it useless, or cuts or disables the tongue, nose, ear or lip, is guilty of mayhem.

[4][9] Mr. Boronda testified at the trial that he and his wife had visited the San Jose theater, and that the attack was unprovoked.

As reported in the Santa Cruz Sentinel, "Her only excuse is that she wanted to be revenged on Boronda, whom she believed intended deserting her and leaving for Mexico.