Objective: This paper presents a systematic bibliometric analysis of the literature on intangible valuation, especially environmental intangibles, to analyze the relevance of the subject, the state of scientific knowledge, and research opportunities. Theoretical Framework: Intangible assets are relevant for companies because they can contribute to higher company valuation. Some research studies have successfully classified the different types of intangible assets and developed models to value companies that include them. However, diverse results have not allowed reaching a consensus on their use in company valuation. Method: The Knowledge Development Process-Constructivist (ProKnow-C) methodology was used; articles on intangible assets were analyzed with the VOSViewer® software, while an analysis of the articles for environmental assets was performed with the lens.org platform. Results and Discussion: It was determined that most intangible asset valuation models are empirical and use regressions to perform the valuation. Intellectual capital is one of the intangible assets that has been proposed by more models. Research Implications: Some opportunities for future research on this topic are identified; these are adjusted to models that consider the main environmental assets and are easily applied by companies.