Mobile apps are an integral component of our daily life. Ability to use mobile apps is important for everyone, but arguably even more so for approximately 15% of the world population with disabilities. This paper presents the results of a large-scale empirical study aimed at understanding accessibility of Android apps from three complementary perspectives. First, we analyze the prevalence of accessibility issues in over 1,000 Android apps. We find that almost all apps are riddled with accessibility issues, hindering their use by disabled people. We then investigate the developer sentiments through a survey aimed at understanding the root causes of so many accessibility issues. We find that in large part developers are unaware of accessibility design principles and analysis tools, and the organizations in which they are employed do not place a premium on accessibility. We finally investigate user ratings and comments on app stores. We find that due to the disproportionately small number of users with disabilities, user ratings and app popularity are not indicative of the extent of accessibility issues in apps. We conclude the paper with several observations that form the foundation for future research and development.