Lynette Grant Sadleir (born 1 August 1963 in Vancouver, British Columbia, Canada) is a former synchronized swimmer.
She competed for New Zealand at the 1984 Summer Olympics in Los Angeles with her sister Katie Sadleir. In the women's duet, Lynette and Katie finished 12th.
After retiring from competition, Lynette was the Synchronised Swimming Coach for the New Zealand teams at three Commonwealth Games in 1986, 1990 and 1994.
She is currently an Associate Professor in the Department of Paediatrics at University of Otago, Wellington, New Zealand. Lynette is a paediatric neurologist and epileptologist.