This Is Acting is the seventh studio album by Australian singer and songwriter Sia. It was released on 29 January 2016 by Inertia, Monkey Puzzle and RCA. Mainly an electropop album, it is mostly composed of songs written by Sia for other female pop artists, but were not included on their albums. Sia described songwriting for others as "play-acting," hence the title This Is Acting.

"Alive", the album's lead single, was released on 24 September 2015. The second single, "Cheap Thrills", was released on 11 February 2016, becoming a top 5 in a number of markets and marking her first number one on the US Billboard Hot 100. The remix of the track featured guest vocals from Sean Paul. A deluxe edition of This Is Acting was released on 21 October 2016 featuring seven new tracks, including the single remix of "Cheap Thrills" and the solo and Kendrick Lamar-assisted versions of "The Greatest".

The album received generally positive reviews from music critics, who complimented the production and Sia’s vocals. However, some criticized the impersonal and indirect nature of the songs. The album debuted at number one in Australia, and also reached number four on the US Billboard 200, selling 81,000 album equivalent units in its first week—of which 68,000 were from pure album sales, becoming Sia's highest first week sales in the country. To further promote the album, Sia embarked on the accompanying Nostalgic for the Present Tour in September 2016.