That is according to a new study conducted by the investment bank Piper Jaffray, which found that 85 per cent of the 8,600 teens surveyed used Instagram at least once a month.
By contrast, 84 per cent of the participants used SnapChat once a month.
However, the rankings were reversed when it came to a question of preference among the teens.
In spite of this, Snapchat recently reported that for the first time ever, the number of people using its service on a daily basis has fallen, prompting its share price to also sink.
On the other hand, Instagram is in a very healthy financial state, with the photo-sharing platform emerging as a hugely valuable tool for marketing.
Piper Jaffray said: "Instagram continues to show dominance in selling, as teens overwhelmingly prefer brands contact them on Instagram versus other channels."
One of the key reasons behind the continued popularity of Instagram - which is owned by Facebook - is the success of its Stories feature.
The concept has proven to be especially popular among teens.