The northern German team beat BM Atletico Madrid on Sunday in a sold out stadium in Cologne 26:21, thanks to a spectacular game from its French goalie, Thierry Omeyer.
The Kiel team has already won the German championship and the DHB Cup, the Hamburger Abendblatt newspaper reported on Monday.
The triple win this year marks the second time since 2007 that the Kiel team has won all three competitions.
Dominant Kiel won all 32 games it played in the Bundesliga.
Kim Andersson, the Swedish national team player, was Kiel's best player on Sunday with seven goals before a crowd of 20,000.
“That was maybe the best Kiel team of all time. It was a super game and we're simply overjoyed,” said team captain Marcus Ahlm.
Although handball is a popular sport in Germany, it still falls far short of support when compared to football, which dominates sports fans and coverage.
But while Borussia Dortmund won both the German football championship and the Cup they didn't make it to the finals of the football Champions League, which was lost by Bayern Munich to England's Chelsea.