नाभिकीय हथियारों, विखण्डनीय नाभिकीय पदार्थों, हथियारों में प्रयोग आने वाली नाभिकीय प्रौद्योगिकी तथा जानकारी का 'नाभिकीय हथियार देशों' से 'अनाभिकीय हथियार देशों' में प्रसार होना नाभिकीय प्रचुरोद्भवन (Nuclear proliferation) कहलाता है।

World map with nuclear weapons development status represented by color. ██ Five "nuclear weapons states" from the NPT ██ Other states known to possess nuclear weapons ██ States formerly possessing nuclear weapons ██ States suspected of being in the process of developing nuclear weapons and/or nuclear programs ██ States which at one point had nuclear weapons and/or nuclear weapons research programs ██ States that possess nuclear weapons, but have not widely adopted them