This thesis aims to find out how animacy affects sentence structure choice in Turkish learners of L2 English. The study compares three different L2 English proficiency levels with each other as well to L1 English and L1 Turkish. In this way the effect of English, a rigid word order language, and Turkish, a free word order language on sentence structure choice have been compared. A picture description task was applied on 94 participants. The pictures depicted a transitive action taking place between an inanimate agent and an animate patient (animate condition) or between an inanimate agent and an inanimate patient. The subjects were given handouts with the pictures and were asked to write down what is happening in each picture. There were 60 Turkish learners of L2 English and 14 English participants in the study. Turkish learners of English belonged to level-1 (16 students), level-2 (25 students) and level-3 (19 students). In addition, 20 Turkish speakers were consulted for their knowledge of Turkish. It was hypothesized that in L2 English, animate entities would be accessed first and this will directly affect sentence structure choice through grammatical subject assignment or through word order. Thus, it was expected that when the learners are shown a picture depicting a transitive action taking place between an animate patinet and an inanimate agent, they would tend to use the passive in English, which assigns both a sentence-initial position and a subjecthood role to the animate entity. L2 proficiency level and native language were expected to play a role in determining the role of animacy on sentence structure choice. Chi-square analysis and odds ratio calculations were made. The results showed that animacy of the patinet affected sentence structure choice in L2 English by triggering the passivce usage in only level-3 (the most advanced group). Animacy of the patient affected native speakers of English in the same way, i.e. native English speakers tended to use the passive voice in the animate condition. No such effect was found in lower level learners of L2 English (i.e. level-1 and level-2) and Turkish native speakers. It was found that in the animate condition, Turkish native speakers tended to use the OSV word order more frequently than they did in the inanimate condition. This result suggested that in Turkish, animacy of the patient triggers the use of the OSV (Object, Subject, Verb) order rather than the passive voice. In short, the research results suggested that L2 proficency level and native language could play a role in determining how animacy affects sentence structure choice in L2.