There is a shortage of studies that have addressed speaking skill with relation to learners' anxiety in Saudi Arabia as EFL context. Therefore, the current study explored Foreign Language Speaking Anxiety (FLSA) in relation to gender within 64 male and 87 female undergraduate Saudi students from different levels. The study examined the causes of FLSA within the learners given gender differences. Mixed- methods design were used in this study. Quantitative data was obtained from a designed survey to collect responses from several Saudi universities and qualitative data collected from students and teachers' interviews. The findings of the study indicated there is no significant difference between genders on the overall measure of speaking anxiety and the causes in FL setting of the study. The study indicated that students with good proficiency level and students who were in higher academic level found to have less speaking anxiety. The prevailing causes of students' speaking anxiety found in the study were: (a) fear of making mistakes, (b) shyness (c) fear of teacher's negative techniques of error correction, (d) fear of their classmates' laugh and remarks, (e) lack of good preparation, and (f) lack of speaking practice in the target language. The study explored that all male and female students and teachers had similar agreement about the negative nature and connotation of anxiety, manifestation and effect of anxiety and they had similar solutions to overcome their speaking anxiety.