This article argues that language provides instructions for the interpretive work of the addressee. The result of this interpretive process is the establishment of linguistic meaning. On this assumption, the article aims at explaining how meaning is established on the basis of the category of mood in Spanish. It is often assumed that the meaning of mood in Spanish is explainable in terms of assertion vs. non-assertion. Contrary to this, we shall claim that assertion belongs to the level of subordination. Instead of the assertion theory, it is suggested that mood may be explained with reference to the notion of factuality. This claim is tested by means of an analysis of mood in complementizer phrases.