She was honoured for her role in the acclaimed Nordic drama 'The Danish Girl', playing Danish artist Gerda Wegener in a love story about how she and her fellow artist husband Lili Elbe played by British actor Eddie Redmayne, navigate his journey as a transgender pioneer.
"Eddie, there you are. Thank you for being the best acting partner. I could have never done it without you. You raised my game," Vikander said late on Sunday in Hollywood in her acceptance speech.
"I want to thank my friends and my mum and dad – thank you for giving me the belief that anything can happen, even though I would have never believed this."
She bested fellow nominees Jennifer Jason Leigh ('The Hateful Eight'), Rooney Mara ('Carol'), Rachel McAdams ('Spotlight') and Kate Winslet ('Steve Jobs').
Her co-star Redmayne however, who had been nominated for best actor for the same movie, lost out to to Leonardio DiCaprio and 'The Revenant'.
Denmark's 'A War' (Krigen) failed to win the Best Foreign Language Film category, losing out to Hungarian WW2 drama 'Son of Saul'. The Tobias Lindholm film has performed well in US theatres and has been sold to at least 20 other countries, but nevertheless will leave Hollywood without an Oscar.
In the Best Documentary Feature category, Joshua Oppenheimer's 'The Look of Silence' was beaten by 'Amy', an inside look at the life of deceased singer Amy Winehouse. Oppenheimer is an American but has lived in Copenhagen for five years and his film was produced by the Danish company Final Cut for Real.