Winslet won the Emmy for her role in Mildred Pierce, a drama about a woman who bakes her way out of poverty.
Downton Abbey's awards included best mini-series and best supporting actress for Dame Maggie Smith.
Accepting her award, Winslet said that she wouldn't be where she is today without her mother's influence.
"It doesn't matter how old you are or what you do in your life, you never stop needing your mum and I will never stop needing mine, so thanks mum, thankyou so much," she said.
