Interviews were conducted with 10 individuals who had great difficulty in completing a thesis, and with 6 students who had relatively little difficulty. A hierarchical structure of categories encapsulating the respondents' accounts was developed through the use of the grounded theory method of qualitative analysis. In this structure, control over the thesis is the core category and is supported by the two properties of dependence—independence and structuring the task. The latter property is in turn supported by project meaningfulness, political expertise, and time management. The relationships among the categories are cast into a grounded theory of thesis blocking. The implications and limitations of the theory are discussed.