This dissertation investigates licensing conditions of dependent indefinite pronouns, such as negative concord items and pronouns that depend on the presence of a c-commanding quantifier. In Chapter 2, I examine freestanding negative concord items in Russian. I provide a novel empirical generalization that freestanding negative concord items are found only in small clause predicates and complements of prepositions. Based on the availability of double negation readings for sentences with freestanding negative concord items and sentential negation, I argue that these items are licensed by a phonologically null negative head, which has a different distribution from the Russian negative head "ne" "not". "Ne" co-occurs with TP, whereas the null negative head occurs in TP-less clauses. I also provide an analysis of the feature checking relations between negative concord items and negative heads. On the theoretical side, the chapter provides evidence that the driving force of movement is located in the moving element. In Chapter 2, I take the position that negative concord items cannot contribute a negative meaning. In Chapter 3, I examine two arguments in favor of the position that negative concord items can contribute a negative meaning, namely their acceptability in elliptical fragment answers and certain cases of double negation readings of sentences with a sentential negation and negative concord items in Spanish and Russian. I show that, at least for the two arguments examined, the conclusion that negative concord items can introduce a negative meaning is not necessary, the additional negative meaning having a source other than negative concord items. In Chapter 4, I examine a series of dependent indefinites in Russian, the "-nibud'"-series. I discuss the licensing of "-nibud'" in modal environments and by quantificational NPs/adverbs. I show that quantificational NPs that license "-nibud'" are strong quantifiers, where strength is defined in terms of an existence presupposition. I also show that "-nibud'" affects the scope of its licenser. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]