Spain has never legislated against bestiality but the new petition could change that, Spanish newspaper El Periódico reported.
The petition, carried out by the non-profit animal rights group the Observatorio Justicia y Defensa Animal, calls for bestiality to be classed as a crime under Spain’s penal code.
Under the slogan "we are not sexual objects" the group has collected signatures on the website change.org.
The petition will now be presented to Justice minister Rafael Catalá when the Spanish Parliament discusses amendments to a new law which will reform the penal code (Ley Orgánica de Reforma del Código Penal), which could be passed as soon as January 2015.
The animal rights group launched the campaign in April 2013 with a judicial report which called for various urgent reforms to improve the legal situation of animals in Spain.
The reforms included a lengthening of the maximum sentence for animal cruelty from one year to three years and criminalizing the use of animals for sexual purposes.
Other European countries such as Germany, the Netherlands, the UK and France have already criminalized bestiality, with Sweden bringing in a new law early in 2014.
Campaigners say that if abusers go completely unpunished and without reform, Spain risks becoming "a paradise for animal sexual abusers".
For the group’s lawyer Nuria Menéndez de Llano "these practices are much more common than you would think and it would be a grave error to let this opportunity to improve legislation pass, considering the present legal vacuum in relation to animal sexual abuse".