This dissertation examines relative clauses in Spanish. The introduction compares various characteristics of Spanish and English relative clauses, while chapter 1 contrasts restrictive and appositive relative clauses. The question of which relative forms should be generated by the grammar in both types of clauses is considered. Chapter 2 handles restrictive relative clauses whose underlying head is a definite, nonhuman PRO and those whose underlying head is a human PRO, either definite or indefinite. Chapter 3 discusses infinitival restrictive relative clauses, and chapter 4 initially deals with the feature (INDIVIDUAL) in relation to relative clauses. A more detailed examination of the underlying structure and surface structure of restrictive relative clauses follows. The feature (CARDINALITY) is seen to play a role in determining the surface relative form which occurs in restrictive clauses. Sample derivations are offered. The chapter concludes with a tentative formulation of rules which account for the various restrictive relative forms. Chapter 5 is a preliminary examination of comparative clauses. The underlying structure of the quantifier phrase and the "mucho/muy" complementarity are discussed, and comparative clauses and restrictive and for various comparative sentences, including certain comparisons of equality and for various comparitive sentences, including certain comparisons of equality and comparisons of inequality. (Author/CLK)