The topic of this article is non-finite complement clauses in Tuvan and their counterparts in Turkish. Tuvanian non-finite complement clauses which are formed with participle and infinitive suffixes (-GAn, -(V) r, -vAK)link to the main clause as a subordinate clause and function as arguments of matrix clauses (subject, direct object and indirect object). In this article, nominal complements are examined synchronically in terms of their morphological properties, syntactic structure and functions, semantic features and tense-aspect functions. Moreover, whether nominal complement clauses are factive and non-factive are dealt with in detail. In this study based on description of Standard Tuvanian and Altay Tuvanian which is considered to be a dialect of Tuvanian, the functions of nominal complement clauses are scrutinized with Modern Turkish in terms of different aspects. Thus, two different Turkic languages are compared with nominal complement clauses.