Background: Palliative care is essential in the care of people with advanced dementia, due to the increasing number of patients requiring care in the final stages of life. Nurses need to acquire specific knowledge and skills to provide quality palliative care. The questionnaire on Palliative Care for Advanced Dementia (qPAD) is useful for assessing knowledge and attitudes toward palliative care, but its adaptation to the Spanish language and analysis of its effectiveness and usefulness for the Spanish culture is lacking. Objective: To report on the Spanish language adaptation and psychometric analysis of the qPAD. Methods: The Questionnaire on Palliative Care for Advanced Dementia Spanish version (qPAD-SV) was obtained from a process that included translation, back-translation, comparison with other language versions, expert review, and pilot study. Content validity, criterion validity, and reliability of the questionnaire were analyzed. The difficulty and discrimination indices of items composing the knowledge subscale were also calculated. Results: Adequate content validity index obtained after the analysis of qPAD-SV by a heterogeneous group of experts was found (overall CVI = 0.96; 0.95 for the Knowledge subscale and 0.99 for the Attitudes subscale). Significant correlations with the Palliative Care Knowledge test (rho = 0.368, p < 0.001) and Self-Efficacy in Palliative Care Scale (rho = 0.621, p < 0.001) show an adequate criterion validity. Cronbach's alpha coefficients for the Knowledge subscale (0.60) and the Attitudes subscale (0.91) supported the reliability of the qPAD-SV. The questionnaire had an overall difficulty index of 0.71, with three items that could be considered difficult or very difficult, and eleven items that could be considered very easy. Discussion: Although it shows internal consistency, validity, and difficulty indices similar to those obtained by qPAD versions in other languages, a reformulation of the items with lower content validity or discrimination indices and those that show difficulties in their comprehension is an aspect to be taken into account to improve this tool. Conclusions: The qPAD-SV is a useful instrument in Spanish to measure the knowledge of Spanish nurses in palliative care and is suitable for international comparisons.