The pop star, 26, had just finished a performance on May 22 2017 when a terrorist detonated a homemade explosive device, killing 22 people and injuring hundreds more.
Grande returned to Manchester two weeks later for an emotional benefit concert, 'One Love Manchester'.
Writing on Instagram ahead of Friday's anniversary, Grande said: "I want to take a moment to acknowledge and send my love to everyone that is feeling the sadness and tremendous heaviness of the anniversary coming up this week.
"Not a day goes by that this doesn't affect you and all of us still. I will be thinking of you all week and weekend. My heart, thoughts and prayers are with you always."
Grande added a black heart and a bee emoji. The bee, representing Manchester's industrial past, became a symbol of hope in the wake of the attack.
Homegrown terrorist Salman Abedi, 22, carried out the atrocity, which killed 22 men, women and children. The youngest victim was eight-year-old Saffie-Rose Roussos.
In March Abedi's brother, Hashem Abedi, was convicted of the murders after a court heard he helped plot the bombing.
Grande returned to Manchester for the first time in over two years last August, when she performed at the city's Pride event.
Her June 2017 One Love Manchester concert featured superstars including Justin Bieber, the Black Eyed Peas, Coldplay, Liam Gallagher and Katy Perry, and raised millions of pounds for victims and their families.