Mary Rebecca "Mamie" Dowd Walker (May 11, 1880 – July 12, 1960) was a jurist and civil leader in Durham, North Carolina, United States.
She became North Carolina's first female judge when in 1934 she was appointed to preside over Durham's juvenile court.
Working with other public servants, Walker introduced countywide reforms to combat delinquency pushing alternatives to incarceration, including prevention and rehabilitation.
Her methods were adopted by other United States courts.