Localytics' statistics suggest sales of the Android handset spiked around the same time of Apple's patent victory over Samsung, and again when the iPhone 5 was unveiled.
Galaxy S3 sales rose by around 16% between August 21 and August 27, with a US court awarding Apple $1 billion (£620 million) in damages at Samsung's expense on August 24.
The surge suggests customers may have feared that the handset would be pulled from stores, and rushed out to purchase it before an injunction could be enforced.
Localytics reports that Galaxy S3 sales spiked for a second time between September 11 and September 17, rising by 15% following a week of no growth. The iPhone 5 was unveiled on September 12, suggesting that numerous customers chose the Samsung device in favour of it.
Apple's iPhone 5 launched to extremely high sales figures, shifting more than 5 million units in its first weekend, but the Galaxy S3 has maintained an average weekly growth rate of 9% since its release, even with the recent spikes excluded.