Niki is the second child of Ken and Barbara Taylor, and grew up in Pembroke Pines, Florida. She has an older sister, Joelle, who is 25, and a younger sister, Krissy, who died in July 1996 aged only 17. Niki was married to Matt Martinez, but split in early 1996. The couple had two children together, twin boys called Jake and Hunter. Niki is currently dating Rob Neidermayer.

Living separately now in Fort Lauderdale, Florida, Niki has a nanny who looks after her twin boys. Despite being a supermodel in high demand commanding high wages, Niki still manages to keep away from the hectic lifestyle associated with being a supermodel. She regards modelling as work and purely that. When she is not modelling, she cares for her children and enjoys spending a lot of time being a normal mother.

Niki is very much an outdoor person. She enjoys all manner of water sports including jetskiing, scuba diving, and hydroslyding. Niki also enjoys cooking.

Niki started modelling at the age of 14 when her parents sent Niki to Miami for some test shoots. During these shoots a photographer noticed her, this culminated in an apperance on the cover of Vogue a year later. At 17, Niki became the youngest model to sign an exclusive contract with Cover Girl. This grossed her a massive $2.4 million. Since then she has created four exclusive calendars of herself, appeared in Cover Girl TV adverts, graced the catwalks around the world in top designer clothes, and appeared on countless magazine covers. She has become one of the world's top supermodels, her beauty, body, and charm shining through in every photograph of her.

Despite giving birth to twin boys, Niki still has a fabulous figure. During pregnancy, she ate constantly, her weight rising to nearly 200 pounds. To combat this, she did a lot of walking during those months. It took her a year to fully get back into shape after the birth. Niki runs every morning and goes to the gym two to three times a week. Niki prefers to wear jeans, sweatpants and sundresses, rather than the designer clothes she models. She would rather eat at home than in restaurants. Her worst habit is chewing gum and once got caught at school doing so, holding up an entire Vogue shoot! Niki did smoke but stopped when she became pregnant. Niki could be interested in doing television in a few years, already hosting MTV's 'House of Style' once before. She has said, "Maybe I could do some acting in the near future. Something where I am not a model or a prostitute or a bimbo -- something challenging." Niki's motto is, "Stick to the basics, hold on to your family and friends - they will never go out of fashion."