Background: Atopic dermatitis (AD) is characterized by microbial dysbiosis, immune dysregulation, and an impaired skin barrier. Microbial dysbiosis in AD involves a reduction in diversity primarily driven by an increased abundance of Staphylococcus aureus. Tralokinumab, an approved treatment for adults with moderate-to-severe AD, improves the skin barrier and immune abnormalities by specifically targeting the interleukin 13 cytokine, but its impact on the skin microbiome is unknown., Objective: To investigate how tralokinumab affects the skin microbiome by examining the lesional skin of adults with moderate-to-severe AD from the phase 3 ECZTRA 1 trial (NCT03131648)., Methods: Microbiome profiling, S aureus abundance, and biomarker data were assessed in a subset of ECZTRA 1 participants (S aureus abundance at baseline and week 16; microbiome profiling at baseline, and week 8/16; and serum sampling before dose and week 4/8/16/28/52)., Results: Tralokinumab treatment led to increased microbial diversity, reduced S aureus abundance, and increased abundance of the commensal coagulase-negative Staphylococci., Limitations: Limitations include a lack of S aureus abundance data at week 8, sampling site variation between participants, and possible influence from concomitant systemic antiinfectives., Conclusion: Our findings indicate specific targeting of the interleukin 13 cytokine with tralokinumab can directly and/or indirectly improve microbial dysbiosis seen in AD skin., Competing Interests: Conflict of interest Dr Beck has been a consultant for Allakos, Arena Pharmaceuticals, DermTech, Evelo Biosciences, Galderma, Incyte, Janssen, LEO Pharma, Merck, Numab Therapeutics, Pfizer, Rapt Therapeutics, Regeneron, Ribon Therapeutics, Sanofi/Genzyme, Sanofi-Aventis, Stealth BioTherapeutics, Trevi Therapeutics, Union Therapeutics and Xencor; DMC member for Novartis; and investigator for AbbVie, Astra-Zeneca, DermTech, Kiniksa, Pfizer, Regeneron, and Ribon Therapeutics. Dr Bieber has been a speaker, and/or consultant, and/or investigator for AbbVie, Allmiral, AnaptysBio, Arena, Asana Biosciences, ASLAN pharma, Bayer Health, BioVerSys, Böhringer-Ingelheim, Bristol-Myers Squibb, Connect Pharma, Dermavant, Domain Therapeutics, Galderma, Glenmark, GSK, Incyte, Innovaderm, IQVIA, Janssen, Kirin, Kymab, LEO, LG Chem, Eli Lilly, L´Oréal, MSD, Novartis, Numab, OM-Pharma, Pfizer, Pierre Fabre, Q32bio, RAPT, Sanofi/Regeneron, and UCB. He is founder and chairman of the board of the non-profit biotech “Davos Biosciences.” Dr Weidinger received institutional research grants from La Roche Posay, LEO Pharma, and Sanofi Deutschland GmbH, and lecture and/or consultancy fees from AbbVie, Almirall, Eli Lilly, Kymab, LEO Pharma, Pfizer, Regeneron, and Sanofi-Genzyme. He is involved in performing clinical trials with many pharmaceutical industries that manufacture drugs used for the treatment of psoriasis and atopic dermatitis. Dr Tauber is an investigator for AbbVie, Boehringer Ingelheim, Eli Lilly, Galderma, LEO Pharma, Pierre Fabre, and Sanofi-Regeneron; a consultant or advisory board member for AbbVie, Eli Lilly, MEDAC, and Sanofi-Regeneron. Dr Saeki has received lecture fees from Kyorin, Kyowa Kirin, LEO Pharma, Maruho, Mitsubishi Tanabe, Sanofi, Taiho, and Tokiwa; and scholarship donations from Esai, Maruho, Mitsubishi Tanabe, and Torii. Dr Irvine reports personal fees (Speaker fees and Consulting fees) from AbbVie, Arena, Dermavant, Eli Lilly, LEO Pharma, Pfizer, Regeneron, and Sanofi. Dr Eichenfield has been a scientific adviser and/or clinical study investigator for AbbVie, Almirall, Asana, Aslan, Dermavant, Eli Lilly, Forte, Galderma, Glenmark, Incyte, LEO Pharma, Novartis, Ortho Dermatologics, Pfizer Inc., Regeneron, and Sanofi-Genzyme. Dr Werfel received lecture and/or consultancy fees from AbbVie, Almirall, Galderma, Eli Lilly, Janssen/JNJ, LEO Pharma, Novartis, Pfizer, and Regeneron/Sanofi. Drs Arlert, Jiang, and Røpke are employees of LEO Pharma. Dr Paller has been an investigator for AbbVie, Incyte, Eli Lilly, and Regeneron; Data Safety Monitoring Board for AbbVie, Bausch and Galderma; and consultant for AbbVie, Almirall, Anaptysbio, Arena, BiomX, Boehringer Ingelheim, Eli Lilly, Forte, LEO Pharma, Novartis, Pfizer, Regeneron, and Sanofi-Genzyme., (Copyright © 2022 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)