The pop star had just finished playing at the venue on 22 May, 2017, when a terrorist detonated a homemade explosive device, killing 22 people.
Writing on Instagram, Grande shared a message of solidarity with the victims.
"Not a day goes by that this doesn't affect you and all of us still," the 26-year-old wrote.
"I will be thinking of you all week and weekend."
Acknowledging "the sadness and tremendous heaviness of the anniversary", she added: "My heart, thoughts, prayers are with you always."
The star signed off with 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.
Grande, who said she suffered PTSD as a result of the atrocity, returned to Manchester last year to headline the city's Pride festival.
The bombing was carried out by Manchester-born Salman Abedi. The youngest of those who died was eight years old. Almost 1,000 people were injured.
The terrorist's brother, Hashem Abedi, was convicted of murder earlier this year for his role in planning the attacks. His sentencing has been postponed due to travel restrictions in place due to the coronavirus.
The pandemic has also affected plans for this year's memorial to the victims, with social-distancing measures putting a halt on church services.
It means Manchester Cathedral will have to broadcast two services on its Facebook page, urging people to log on at home rather than attend in person like previous years.
"Before the restrictions, it was really important we had connectedness and reached out, family and friends, but also the wider community, to come together," said Figen Murray, whose son Martyn Hett died in the attack.