For me, there wasn't really that "ah ha" moment. It was more of a gradual awakening. It began with questions, accelerated with actually reading The Bible (multiple versions, multiple times,) and if there was a "Eureka!" event it was simply the realization that my quest for understanding had led me to atheism.

When I realized the word God doesn't correspond to anything specific in reality.

I've knew all my life.
Unfortunately my own mother's hypocrisy revealed how much religion was bs to me when she would be in church raising her hands up to the "lord", crying in the aisles and shaking from the "holy Spirit", but would come home and continue to drink, smoke and cuss up a storm that Sunday night.
I realize church was a side show when I saw that people came to church to be seen.
Church kept up your reputation in the neighborhood...
And don't even get me started on that "holy book"...

When I realized my faith was the only thing supporting such nonsense.

When I found out fairies,santa etc was a lie!

Every time I learn something new that supports a scientific perspective is an aha moment for me. It's been a slow gradual process for me, and continues to be as I understand new concepts based on science and reason.

For me, it is the key word is 'Righteous'. They all want to be 'Righteous', which is fair enough, but are they actually 'Righteous' or merely 'Self Righteous ??'

Many years ago when George carlton explained it in a comedy routine.

No "ah ha" moment over religion for me as I was a skeptic even as a child. I did sort of have one over supernatural phenomenon when I read a book about pyramid power and it dawned on my just how stupid it all was. I subscribed to Skeptic Magazine and never looked back.[skeptic.com]

Religion never quite clicked with me in the first place. I was brought up Presbyterian. When I was 17 I traveled to Alaska to help in building a church. I had an 18 year old helper and we worked 6 days a week and went to that church on Sunday. One day I told my partner that I was too tired to go to church. He was very upset and finally I blurted out--I'm not even a Christian! He blind sided me and almost knocked me out. I was bleeding all over. Later he went to another place in Alaska and I was told I did not have to work on the church anymore--instead I was to read the book of John. I did that but read other parts of the bible also! Wow! was the bible so evil!

I took native American history and women's rights at the u of m and then figured christianity was bs.Dont think God, then man, then woman are the order of things and our destiny was not manifest destiny but critical or we are doomed environmentally, which has come to pass. PLus I don't believe in hell.Hell is actually here on earth.

My nature has been to question everything, so I was already edgy at a very young age when I stumbled on the book "Why I am NOT a Christian" by Bertrand Russell. I read it with lively interest without even knowing who Bertran Russell was at the time. The rest is history, I have been guilt free pretty much my whole life thanks to that book.

My adolescence wasn't religious in any way. Although she was raised southern baptist, my mother saw the contradictions within christianity. When I was old enough and began to ask questions, she sat the bible down in front of me and had me read 5 pages a day till I finished. As I read she'd answer questions and point out inconsistencies and contradictions. By the end I couldn't understand why anyone would devote their lives to a bunch of fairytales from thousands of years ago. I did a bit more reading on other religions but they all felt the same which basically told me they were all a sham. So, in a nutshell, I've been a non-believing heathen my whole life and until demonstrable proof is displayed I shall stay this way.

I always thought it was bullshit

I decided to read the holy babble word for word....and it turned me into an atheist.

When the bible depictions in ‘Sunday school’ didn’t match known reality…

We get this question several times a week from new members.

I thought the Bible's Hebrew god was bloodthirsty and cruel, but finally stopped attending church when I saw how misogynistic and racist the Christians were. I stopped believing in Christianity altogether when I read the Sumerican texts, since it was so plain the Bible had been copied from them.

Praying and then realizing that it was likely that I just placeboed myself. After that happened, I began examining my beliefs for the first time. I even read some of the bible. I examined these beliefs and concluded that I had no good reason to hold them after about two years. I think it finally clicked after binge watching debates w/christopher hitchens, I was finding it hard to find good reason to continue holding such fragile and unsubstantiated beliefs. It's easy to be a christian when you don't read your own holy text and just parrot the watered-down version taught to you by the priest. Afterall, ignorance is bliss.

Left the church at 14, quit believing in God in my 20's. I don't remember a moment when l consciously thought "l don't believe anymore". It was more like a slow leak.