This study aimed to explore the effects of synectics as a prewriting technique on writing fluency and lexical complexity in the written texts of 20 tertiary level Turkish EFL learners. To this end, a mixed research design was adopted combining both quantitative and qualitative techniques. Repeated measures design was employed to examine the differences in participants' writing fluency and lexical complexity over time, and to gain a deeper understanding of learners' experiences, semi-structured interviews were conducted. The learner-written texts were analyzed using VocabProfile (VP), an online text analysis program, with respect to fluency and lexical complexity. Descriptive statistics, Friedman test for repeated measures, and Wilcoxon Signed Ranks test were carried out as data analysis procedures. As for the analysis of the qualitative data, inductive content analysis was performed. The findings revealed that the participants' writing fluency increased significantly at the end of the program. On the other hand, their lexical complexity remained the same during the study. In terms of the results of the qualitative analysis, the participants had mostly positive perceptions about their synectics experience in terms of vocabulary learning, improvement of writing skills, and attitudes to writing.