This report focuses on a study of three affective variables in second language acquisition: anxiety, self-concept, and timidity. The study was conducted on 92 high school English-as-a-foreign-language students in Barcelona, Spain. Subject performance was measured by the State-Trait Anxiety Scale, the Spanish version of the Tennessee Self-Concept Scale, the Social Reticence Scale, and a cloze test. Results of the study showed that a degree of classroom anxiety was the only statistically significant variable of the three studied, explaining 32% of the variance with level of proficiency. (SR)