The five-year-old's funeral was held on Sunday, after he tragically lost his battle with cancer on Thursday afternoon.
On Monday proceedings in the assembly began with tributes to Oscar, led by First Minister Peter Robinson.
"Absolutely everybody who met him was won over by his personality, by the mischievous innocence of the young boy," he said.
"When the deputy First Minister and I met him and he turned the office upside down, you'd almost be exhausted after he left, there was so much energy displayed.
"I think it's right to honour somebody who has shown such fortitude in the face of adversity, brought so much joy and indeed so much love to so many people.
"It is of course sad that he has passed and I think the words would've brought tears from any stone, were the words in the midst of his suffering, he said that 'I didn't want to be a boy anymore', and that indicated somebody who had fought so hard and for so long, [but] was suffering so much, so today we pass our condolences to Stephen, to Leona and wee Izzie."
He had a way of making you smile, you couldn't be in his presence without smiling.
Deputy First Minister Martin McGuinness also said he treasures the day that Wee Oscar came to visit.
"The day he came to Parliament Buildings was an incredible day, probably one of the most memorable days in the history of this assembly," he said.
"He caused mayhem, he was like an exocet missile running right through the building and we absolutely loved it.
"Oscar was a wonderful and very special little boy at five years of age, who had such an impact on all of us."
It was Stephen Hawking that said we are very small, but that we are profoundly capable of doing many great things and Oscar Knox was very small, only five years of age, but absolutely profoundly capable of doing many great things.
Mr McGuinness described Wee Oscar as a "unifier" in Northern Ireland.
He added: "It's heartbreaking for me to look at that photograph of him standing on my desk, with his little arm around the First Minister's shoulder and my shoulder, because that sends a message, 'I depend on you guys', and I think all of our children who are out there, depend on all of us. So we have to rise for the occasion."
Over 1,000 people attended the 'Mass of the Angels' at St Bernard's Church in Glengormley ahead of a private cremation on Sunday.
In April last year, Wee Oscar was given the all-clear, but sadly the cancer returned a few months later.
After Oscar was originally diagnosed with neuroblastoma at the age of two, the Knox family mounted a social media campaign in a bid to raise funding and awareness for treatment and the little boy became well-known and loved by the Northern Ireland people as well as further afield.
Over £32,000 has been raised through a special Just Giving page after the Knox family asked for donations to be made to Northern Ireland Children's Hospice and the Haematology Unit at The Royal Belfast Hospital for Sick Children in lieu of flowers.
Siofra Healy from NI Children's Hospice said the amount raised in tribute to Oscar was "phenomenal".
"Every year at the Children's Hospice we need £3m to run the service, we rely on the support of the community to run those services every year for 300 children," she said.
"We do get a lot of money in memory from families throughout the year, but Oscar touched so many people."
Wee Oscar was a Celtic fan and the club players wore black armbands as a mark of respect during Sunday's home match with Dundee United. A tribute was also shown on big screens before the game at Celtic Park where fans stood to sing You'll Never Walk Alone.
On Sunday night, Belfast also paid a special tribute to the brave boy, as the city hall was lit up in blue and yellow - the colours of #TeamOscar - in his memory.
Many people also lit Chinese lanterns as their own personal tribute and numerous lights could be seen twinkling in the sky for Oscar.