This two—volume set (CCIS 1565 and CCIS 1566) constitutes selected and revised papers from the 16th International Conference on Bio—Inspired Computing: Theories and Applications, BIC—TA 2021, held in Taiyuan, China, in December 2021. The 67 papers presented were thoroughly reviewed and selected from 211 submissions. The papers are organized in the following topical sections: ​evolutionary computation and swarm intelligence; DNA and molecular computing; ​machine learning and computer vision.