Carlo Ancelotti's men have had yet another stunning season, adding this prestigious trophy to their La Liga triumph, in which they finished 10 points ahead of rivals Barcelona.
Madrid looked second best for most of the night but found the key breakthrough on 74 minutes via the unlikely source of Dani Carvajal, who glanced home a deft header for his first Champions League goal in five years.
Los Blancos wrapped up the victory less than 10 minutes later when Ballon d'Or candidate Vinicius Jr powered a left-footed strike past a helpless Gregor Kobel.
Read a full report of the final here.
Madrid's run to the final started with a flawless performance in the group stage, winning six from six against Napoli, Braga and Union Berlin.
They then battled past Leipzig 2-1 in the last 16, before producing a superb defensive showing against Manchester City in their quarter-final second leg which saw them go through following a penalty shootout.
They overcame another incredibly tough test against Bayern Munich in the semi-finals, with former Stoke City striker Joselu bagging two dramatic late goals to see them qualify for the final.
It is the perfect way for legendary midfielder Toni Kroos to say farewell, with the German retiring this summer after Euro 2024. It is his sixth Champions League title overall - his fifth at Madrid to go alongside his one at Bayern Munich.
For Borussia Dortmund, it is a heartbreaking end to what has been an inspiring run in Europe this season.
After initially topping a perilous group with Newcastle, Paris Saint-Germain and AC Milan, Dortmund knocked out PSV, Atletico Madrid and the French champions on their way to the final.
Their league campaign had been far more underwhelming though, securing just a fifth-place finish in the Bundesliga. However, due to German clubs' performances in Europe, they will still qualify for the Champions League next season.