The Manchester-headquartered fast-fashion firm said pre-tax profits rocketed 129% to £14.3m in the six months to 31 August, while sales rose 40% to £127.3m.
Boohoo said its performance was driven by its core womenswear ranges, plus-size and petite clothing and a standalone menswear website, where sales have doubled.
Boohoo saw growth in every geography, with revenue rising 38% in the UK, 41% in Europe and 93% in the US.
The company said the collapse of sterling against the US dollar has "not significantly" affected its results because it has hedged against currency fluctuations.
However, it added that a weaker pound "does provide the opportunity to use promotional activity to generate incremental international sales", adding: "It remains to be seen what the longer term effect of continued sterling weakness might be in the supply chain."
The firm's joint chief executives, Mahmud Kamani and Carol Kane, said that, as a result of the strong results, they now expect revenue growth for the full year of between 30% and 35%.
They added: "Through our constant focus on what matters to our customers, together with our investment in technology and operational improvements, we will continue to deliver profitable growth."