The association between speaking anxiety and L2 speech production, including L2 pronunciation, remains largely under‐researched, especially in relation to task complexity. The present study investigates the effect of task complexity on speaking anxiety and their impact on specific dimensions of L2 speech production: speaking fluency (speed, breakdown, and repair) and accuracy (grammar, lexis and pronunciation); and global assessments of L2 speaking performance: accentedness and comprehensibility. Forty‐two Spanish learners of English performed simple and complex versions of a monologic oral narrative task. The results indicated that task complexity affected learners’ anxiety levels and was detrimental to their L2 speaking fluency, pronunciation accuracy, and accentedness. Moreover, higher self‐perceived anxiety was associated with lower breakdown fluency and less lexico‐grammatical accuracy. Last, once the contributions of L2 proficiency and working memory were controlled for, anxiety accounted for a significant 13%–15% of variance in breakdown fluency.