Pikiteora Maude Emily Gertrude Edith "Pixie" Williams (married name Costello; 12 July 1928 – 2 August 2013) was a New Zealand singer best known for the song "Blue Smoke", recorded in 1949.

When she was 17, Williams moved to Wellington, finding work in a factory and living at the YWCA hostel on Oriental Parade.

A self-taught singer, Williams was recommended to Karaitiana by his fiancée Joan, who had sung with her whilst staying at YWCA hostel in Wellington.

[2][7] After a funeral in Upper Hutt, Williams was buried with her husband at Green Park Cemetery in Waldronville, Dunedin.

[6][9] On 2 October 2019, Williams, along with Ruru Karaitiana and Jim Carter, was inducted into the New Zealand Music Hall of Fame, to mark the 70th anniversary of the release of "Blue Smoke".