Barbara Greer, who lives in Chelmsford, was nominated by her friend Nicole Hardy on behalf of 11 year old Jack who struggles to do anything for himself.
The annual competition, organised by Britain's largest Christian broadcaster, Premier Christian Radio, invited sons and daughters up and down the country to nominate their mothers for the 'Mum of the Year' accolade in no more than 200 words.
In her nomination on behalf of Jack, Nicole explained that Barbara had always put Jack first in her life.
"She was told that Jack wouldn't talk so she learnt Makaton to teach him how to sign which, to everyone's amazement, he did," said Nicole.
"She eventually taught him how to speak and how to do other things we all take for granted.
"Barbara regularly helps other families with children who have disabilities, advising them on how to obtain help for their specific needs and how to fill-in all the lengthy forms."
Premier's Programme Director, Dave Rose said: "We were looking for mums who had achieved something extraordinary over the previous twelve months, and Barbara has clearly done that."
In her nomination letter, Nicole explained how she'd asked Jack why his mother should be 'Mum of the Year'. He said it was because he loved her and that she was "very nice."
She added: "Although Jack can't write this letter to you, he is an amazing young man and is a credit to all the hard work, tears and love Barbara pours out on him."
The UK's first woman bishop, Libby Lane, was a member of the 'Mum of the Year' judging panel.
She told Premier: "The thing I will be most proud of when I come to the end of my life is my children. A good mum is one who loves her children - and that simply means we do the best we can out of that love."
Runners up included Jeanette Ward of Stoke-on-Trent, Jemima Addison from Barking, Diane Eynon of Blackwood in Wales, and Rachel Ley from Exeter.