Stephen passed away due to an undiagnosed heart defect aged 33 while on holiday in Spain and his death left a gaping whole in the group.
Earlier today, Ronan - who was best friends with Stephen - took to Instagram and shared a photograph of the late Irish star.
Alongside it, he said: "Where has the time gone? Missing ya everyday Bro. Your words still make me laugh. Your song still gets me through.
"Your memory lives on in every song we sing. Rest well my friend God bless. X."
Keith Duffy also posted an array of photographs taken when the band were at the height of their fame.
In a touching tribute, he added: "Can't believe it's been 5 years. We still talk about you everyday. Steo we love you bro, Miss Ya, Till we meet again X."
Shane Lynch, meanwhile, thanked fans for their ongoing support: "Thanks to all for your kind words and support it means alot... #steo," he said.
Mikey Graham has not shared his thoughts publicly.
Following Stephen's death, all four singers flew to Spain and accompanied their bandmate's body back home to Ireland. The following March, they released an album, Brother, as tribute to their close friend.
On 24 November, Boyzone will release their sixth studio album, called From Dublin To Detroit.
Watch Stephen and the rest of Boyzone in their video for 'No Matter What' here: