This dissertation shows that there are syntactic constraints involved in the aspectual interpretation of the VP that involve the internal structure of the verbal complements. Although a simple compositional semantics would predict certain interpretations, the syntactic computational system has its own mechanisms, and the relevant configurations do not always obtain. Consequently, certain readings end up being blocked. Chapter 1 defines the relevant output conditions for aspectual interpretation based on the semantic work of Verkuyl (1995) and Krifka (1989), and proposes a syntactic configuration within the Minimalist Program for Linguistic Theory (Chomsky 1993) at which aspect is calculated. Chapter 2 shows that two classic cases of apparent grammaticalization of aspect, Finnish and Slavic can be reduced to independently needed elements in the grammar: A-quantifiers and movement to AgrO for Case checking. Chapter 3 examines Accusative Clitic Doubling in Spanish and provides a new analysis which accounts for the aspectual interpretations of the construction. Chapter 4 proposes a theory of Determiner Transparency in which definite determiners in relative clauses, certain kinds of adjectives and demonstratives do not select for their head NP and as a result, durative reading of the VP predicate are obtained if the head is non-quantized. Chapter 5 extends the analysis to "type" expressions, measure phrases and possessives (genitives). Chapter 6 provides an aspectual analysis of the copula verbs 'ser' and 'estar' in BrazilianPortuguese, and argues against their being the grammaticalization of the stage-level and individual-level distinction.