This study showcases the collaborative work between, on the one side, the Spanish Ministry of Health, Social Services, and Equality and the Federation of Municipalities and Provinces and, on the other side, a consortium of eight Spanish universities. The aims are to implement a positive parenting policy to adopt codes of professional best practices to improve prevention work with families. Sixty professionals from 30 local agencies collaborated in the drafting of a Guide of Best Practices in Positive Parenting and the development of an e-tool (http://familiasenpositivo.org). The e-tool allows for the assessment of 25 best practices and 188 indicators to improve the quality of positive parenting services, the professional work done with families, and the programmes provided. The process of dissemination among professionals is also described. Results showed that the e-tool is an instrument that is reliable and useful to introduce a culture of best practices and to promote quality assurance in the services.