Despite being there or thereabouts during the campaign, a 30-27 away defeat to Zebre in their penultimate RaboDirect PRO12 clash ended the Osprey's hopes of extending their season.
As it was the region ended the season fifth in the table, four points behind Ulster who grabbed the final semi-final spot.
It was the second year running that the Ospreys have just missed out on the play-offs in fifth but Tandy believes they can make an impression on the top four next season.
"I have a lot of belief we'll be up there [next season]," Tandy told the South Wales Evening Post. "We have a young squad and the boys will be a year older and a year wiser.
"The reality is that young players need to go through tough times as they develop. Rugby isn't a straight line where success just keeps coming. Sometimes, there can be a tough season.
"We don't make excuses, but occasionally injuries or suspensions can stretch you. We went up to Edinburgh with two blindsides in the second row, which wasn't ideal. We lost the game and ultimately that defeat cost us.
"But there is a strong culture here and we are all determined to be there or thereabouts next season.
"Guys like Alun Wyn Jones, Justin Tipuric, Dan Biggar and Duncan Jones are winners through and through. Their influence can only be positive on those around them."
To get your hands on tickets for the RaboDirect PRO12 final, visit http://www.rabodirectpro12.com/final/tickets.php
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