The aim of the present study was to investigate sociolinguistic abilities of Turkish senior students of ELT departments in comparison to native speakers of English. Fifty Turkish and twenty-five American students participated in the study. The study was carried out in two aspects: (1) The differences of refusal and complaint strategies and (2) how their performances were perceived by a native interlocutor for the same social situations with two variables of interlocutors: higher – equal, familiar – unfamiliar. The data were collected qualitatively and quantitatively by means of two tools; a DCT involving 6-paired situations with two interlocutors, in total 12 items, separated as 3 refusal and 3 complaint situations was used for the qualitative analysis. The responses of all participants for each pair were coded, analysed and compared in SPSS program. Quantitative analysis was done by a communicative rating scale. An American rater graded Turkish students’ responses according to the 5-point scale to assess their performances in sociocultural and sociolinguistic criteria. The results showed that Turkish EFL learners could use a range of speech act strategies, but they deviate from native speakers in content. Also, it was seen that they lacked some sociolinguistic and sociocultural knowledge that might cause sociopragmatic failure.