Lemoniz Nuclear Power Plant was a nuclear power plant under construction in Lemoniz, Spain in 1983 when the Spanish nuclear power expansion program was cancelled following a change of government. Its two PWRs, each of 900MWe, were almost complete but were never operated.

Conflict concerning the Lemóniz Nuclear Power Plant was one of the major anti-nuclear issues in the 1970s and 1980s in Spain.

The building of the Lemoniz Nuclear Power Plant was opposed by ETA, a terrorist Basque independentist organisation. The first attack on the site took place on 18 December 1977, when an ETA commando unit attacked a Guardia Civil post which was guarding the station. One of the cell members, David Álverez Peña, was injured in the attack and died a month later. On 17 March 1978, ETA planted a bomb in the reactor of the station, causing the death of two workers (Andrés Guerra and Alberto Negro), and wounded another two. The explosion also caused substantial material damage to the facility, which set back construction.

On 3 June 1979, the anti-nuclear activist Gladys del Estal from Donostia died after being hit by a bullet from the police force Guardia Civil during a demonstration in Tudela (Navarra) on the international day of action against nuclear power. Ten days later, on the 13th of June, ETA managed to get another bomb into the works on the facility, this time in the turbine area. The explosion caused the death of another worker, Ángel Baños. Meanwhile, numerous demonstrations, activities and festivals attended by thousands were being held across the southern Basque Country by ecologists and left leaning groups to demand the closure of the station

The escalation of ETA's actions came to a head on 29 January 1981, when they kidnapped the chief engineer of the power station, José María Ryan, from Bilbao. They gave a week for the facility to be demolished and threatened to kill the kidnapped engineer. Although there was a large demonstration in Bilbao for the liberation of the engineer, and after the deadline for demolishing the station had passed, ETA killed Ryan, causing an outcry and the first anti-ETA strike.

However, the killing of Ryan resulted in the de-facto stoppage of works at the site, and the power company Iberduero, owner of the facilities, officially stopped the works while waiting for the Basque Government to explicitly support continuing the development.