Traditional intellectual capital (IC) frameworks are often too broad to provide actionable recommendations for managers. To overcome this limitation, it has been suggested that more contextually informed frameworks could be developed. Accordingly, the aim of this paper is to identify and classify the knowledge resources that shape IC in the marketing function, as well as to test the content validity of the proposed framework, and to diagnose the strengths and weaknesses of Spanish firms in terms of marketing-related knowledge resources. To identify and classify knowledge assets in the field of marketing, we followed a literature-grounded approach. More precisely, we set out from the IC categories identified in the global IC literature (namely, human capital, organizational/structural capital and social/relational capital) and tried to identify the specific content of each of them in the marketing function, based on its characteristics and recent evolution. Afterwards, we tested the content of the new framework in a group of companies with different profiles (manufacturing/service, B2B/B2C, high-tech/low-tech, large/mid-sized) and carried out a survey in a representative sample of Spanish firms with at least 100 employees to diagnose their situation in terms of marketing-related IC. As a result, this paper presents a marketing-related IC architecture made up of three main categories, nine subcategories and eighty items. Moreover, the survey results demonstrate that marketing-specific human capital is the most developed knowledge resource in Spanish firms, followed by marketing-specific relational capital. On the contrary, marketing-specific structural capital presents the lowest level of development.