A political reform referendum was held in Spain on Wednesday, 15 December 1976, to gauge support for either the ratification or repealing of the Political Reform Act which had been approved by the Spanish Cortes on 18 November 1976. The question asked was "Do you approve of the Political Reform Bill?" (Spanish: ¿Aprueba el Proyecto de Ley para la Reforma Política?). The referendum resulted in 97.4% of valid votes in support of the bill on a turnout of 77.7%.
The table below lists voting intention estimates in reverse chronological order, showing the most recent first and using the dates when the survey fieldwork was done, as opposed to the date of publication. Where the fieldwork dates are unknown, the date of publication is given instead. The highest percentage figure in each polling survey is displayed with its background shaded in the leading choice's colour. The "Lead" column on the right shows the percentage-point difference between the "Yes" and "No" choices in a given poll.