Biological is the adjectival form of "biology", the study of life. Biological may also refer to:

• Biological agent, an infectious disease or toxin that can be used in bioterrorism or biological warfare
• Biological process
• Biological relationship, a measure of the degree of consanguinity

• Biologic (disambiguation)
• Biological material (disambiguation)
• Biological warfare
• Biopharmaceutical, a drug that is synthesized from living organisms or their products and used as a medical treatment
• Organic (disambiguation)