Android adalah sistem operasi untuk peranti bergerak seperti telefon selular, komputer tablet dan notebook. Android dibangunkan olehGoogle berdasarkan sistem perisian Linux dan perisian GNU. Android asalnya dibangunkan oleh Android Inc. (firma yang kemudiannya telah dibeli oleh Google). Kemudian untuk mengembangkan Android, dibentuklah Open Handset Alliance, konsortium daripada 34 syarikat telekomunikasi, termasuk Google, HTC, Intel, Motorola, Qualcomm, T-Mobile, dan Nvidia.
Android mempunyai komuniti yang besar dalam membangunkan serta menulis aplikasi untuk pengembangan fungsi peralatan. Dianggarkan hampir 70,000 aplikasi untuk Android boleh didapati, menjadikanya sasaran pengembangan peralatan kedua paling popular untuk peralatan mobile.
Android's kernel is a fork of the Linux kernel but has further architecture changes by Google outside the typical Linux kernel development cycle.For example Android does not have a native X Window System nor does it support the full set of standard GNU libraries, and this makes it difficult to port existing Linux applications or libraries to Android.
Certain features Google contributed back to the kernel, notably a power management feature called wakelocks, were rejected by mainline kernel developers, partly because kernel maintainers felt that Google did not show any intent to maintain their own code. Even though Google announced in April 2010 that they would hire two employees to work with the Linux kernel community, Greg Kroah-Hartman, the current Linux kernel maintainer for the -stable branch, said in December 2010 that he was concerned that Google was no longer trying to get their code changes included in mainstream Linux.Some Google Android developers hinted that "the Android team was getting fed up with the process", because they were a small team and had more urgent work to do on Android.
However, in September 2010 Linux kernel developer Rafael J. Wysocki added a patch that improved the mainline Linux wakeup events framework. He said that Android device drivers that use wakelocks can now be easily merged into mainline Linux, but that Android's opportunistic suspend features should not be included in the mainline kernel.In 2011 Linus Torvalds said that "eventually Android and Linux would come back to a common kernel, but it will probably not be for four to five years.