Annette McDonald, from Glenmore in Whitburn, said she put the lights up for her young grandchildren - aged six, three and one - to enjoy and has been doing so for years.
The 55-year-old told the Daily Record she proudly has a light-up Santa Claus and star on her house wall, as well as fairy lights across the hedges, windows and doors.
But on Tuesday, she received a "nasty" Christmas card by post from someone who left a surname and claims to live nearby, criticising the display for being "tacky."
In the letter, the woman attacks Mrs McDonald's lights - calling them an "assault on the eyes" and "the worst of the entire estate".
Speaking to the Edinburgh Evening News, Mrs McDonald said: "It did hurt. I happened to be on quite a low that day and after the initial shock, I felt angry.
"I have friends with depression and mental health issues and if they had this card through the door, it could have put them over the edge. It could have been disastrous.
"It totally shocked me that someone could sit and do something like that, not knowing who the person is on the other side of the door."
Later on Tuesday, the estate agent posted a picture of the car on Facebook in a bid to find out who was responsible for penning it.
Mrs McDonald, who moved to the estate in July but has been in Whitburn for years, said she will shortly be chapping the doors of two people she believes may have sent it.
The card read: "Please do something about your Christmas lights, we know you are new to the area, but they're tacky, gaudy and an assault on the eyes.
"The rope lights around the windows and door are awful and we've yet to figure out what the Santa's supposed to be doing - maybe you could take a leaf out of your neighbour's book, if you look at number 74.
"We walk our dogs round Glenmore and your lights are the worst of the entire estate - even your immediate neighbours are saying how bad they are. Less is more!!
"I know you will not do anything about them, but you need to know."
Mrs McDonald disputed that her neighbours had criticised her lights, having spoken to them about the card herself.
And she said that she has received another three Christmas cards since from neighbours to say they were sorry to hear about the letter.
Her Facebook post on Tuesday has since received about 1,000 comments and has been shared more than 730 times.