|Millennium:||1st millennium BC|
|Centuries:||2nd century BC – 1st century BC – 1st century|
|Decades:||40s BC 30s BC 20s BC – 10s BC – 0s BC 0s 10s|
|Years:||18 BC 17 BC 16 BC – 15 BC – 14 BC 13 BC 12 BC|
|15 BC by topic|
|Gregorian calendar||15 BC|
|Ab urbe condita||739|
|Ancient Greek era||191st Olympiad, year 2|
|Chinese calendar||乙巳年 (Wood Snake)
2682 or 2622
— to —
丙午年 (Fire Horse)
2683 or 2623
|Coptic calendar||−298 – −297|
|Ethiopian calendar||−22 – −21|
|- Vikram Samvat||42–43|
|- Shaka Samvat||N/A|
|- Kali Yuga||3087–3088|
|Iranian calendar||636 BP – 635 BP|
|Islamic calendar||656 BH – 655 BH|
|Julian calendar||15 BC|
|Minguo calendar||1926 before ROC
|Seleucid era||297/298 AG|
|Thai solar calendar||528–529|
|Wikimedia Commons has media related to 15 BC.|
Year 15 BC was either a common year starting on Tuesday, Wednesday or Thursday or a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Monday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Drusus and Piso (or, less frequently, year 739 Ab urbe condita). The denomination 15 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
- The Raeti tribes of the Alps are subjugated by Tiberius and Nero Claudius Drusus and the new Roman province of Raetia is established with Chur (in modern-day Switzerland) as its capital. During the campaign, Roman triremes on Lake Constance destroy the fleet of the Vindelici. Augsburg is founded as Augusta Vindelicorum, and becomes the capital of Raetia Prima; and Legio XXI Rapax is stationed at Regensburg in the new province.
- Drusus decides to improve the passage through the Alps for military control of Noricum and Raetia and builds the Via Claudia Augusta through Italy.
- Vienna becomes a frontier city (Vindobona) guarding the Roman Empire against the Germanic peoples.
- Marcus Livius Drusus Libo and Lucius Calpurnius Piso are Roman Consuls.