Sienna Miller is 44 years old as of early 2026.

Quick Scoop

  • Sienna Miller was born on 28 December 1981 in New York City.
  • That birthdate makes her 44 years old as of January 2026.
  • She is an American-British actress known for films like Layer Cake , Alfie , and American Sniper.

Over the past two decades, she has shifted from early-2000s tabloid fixture to a more respected, often under‑rated dramatic actress, which is part of why her age sometimes becomes a small trending topic around new premieres and festival appearances.

TL;DR: Sienna Miller’s birthdate is 28 December 1981, so she is 44 years old now.

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