The acquisition of Titan Aerospace comes as Google continues to develop its Project Loon, which aims to bring internet access to more people by carrying a wifi signal around the world in aircraft, mainly weather balloons.
Titan has been designing two types of high-flying drone, and the purchase comes just weeks after Facebook announced its own drone project to help bring web access to more people around the world. Neither Google nor Titan disclosed the purchase sum.
A Google spokesman said: "Titan Aerospace and Google share a profound optimism about the potential for technology to improve the world. It's still early days, but atmospheric satellites could help bring internet access to millions of people, and help solve other problems, including disaster relief and environmental damage like deforestation.
"It's why we're so excited to welcome Titan Aerospace to the Google family."
The technology works by using unmanned drones, flying at high-altitude, which beam down a wifi signal to remote parts of the world currently lacking internet access.
Titan Aerospace develops drones that are solar-powered and can therefore stay in the air for long periods of times - years, according to the company.
The Titan Aerospace website has already been updated with a statement: "We're thrilled to announce that Titan Aerospace is joining Google. At Titan Aerospace, we're passionate believers in the potential for technology, and in particular atmospheric satellites, to improve people's lives.
"It's still early days for the technology we're developing, and there are a lot of ways that we think we could help people, whether it's providing internet connections in remote areas or helping monitor environmental damage like oil spills and deforestation. That's why we couldn't be more excited to learn from and work with our new colleagues as we continue our research, testing and design work as part of the Google family."
Before announcing their own drone-based internet expansion project last month, Facebook also purchased a drone manufacturer - UK-based Ascenta - for more than £10 million.
The social network is one of the founding members of internet.org, an organisation that also includes smartphone maker Nokia, and has set out with the aim of bringing the internet to parts of the world currently without it.
According to figures published by internet.org, only one in three people can currently get online, and the group argues that more internet users would lead to greater global innovation.