Both funding agencies and scholars in science studies have become increasingly concerned with how to define and identify interdisciplinarity in research. The task is tricky, since the complexity of interdisciplinary research defies a single definition. Our study tackles this challenge by demonstrating a new typology and qualitative indicators for analyzing interdisciplinarity in research documents. The proposed conceptual framework attempts to fulfill the need for a robust and nuanced approach that is grounded in deeper knowledge of interdisciplinarity. As an example of using the framework, we discuss our empirical investigation of research proposals funded by a national funding agency in Finland.