Acknowledging the significance of growth in tourism businesses, this study examined how intellectual capital and innovation influence the expansion of tourism companies in Mashhad, Iran. The research is applied in purpose and descriptive-survey in nature. The statistical population included 700 individuals from tourism firms in Mashhad. Using Cochran's formula, a sample size of 248 participants was determined. A cluster sampling technique was utilized. Data were gathered through standardized questionnaires, whose validity and reliability were confirmed by expert evaluation and by calculating Cronbach's alpha and composite reliability coefficients. Structural equation modeling with Smart-PLS software was used for data analysis. Results revealed that relational capital has a significant impact on both process innovation and marketing innovation within the companies studied. Consequently, it is suggested that tourism companies focus particularly on their relational and organizational capital to promote growth. Additionally, since the mediating effects of organizational and marketing innovation were verified, managers are advised to strategically channel these types of capital toward enhancing organizational and marketing innovation, which can lead to increased profitability and market share.