The Watchtower is a magazine produced on a monthly basis by the Watch Tower Bible and Tract Society of Pennsylvania, distributed by Jehovah's Witnesses as part of their ministry (preaching) work. It's full name is The Watchtower Announcing Jehovah's Kingdom. The Watchtower's stated aim is to "honor Jehovah God, the Supreme Ruler of the universe". It is the most widely circulated magazine worldwide, and its companion magazine Awake! is the second most widely circulated magazine worldwide, according to the article Top 5 World’s Best Magazines.
There is also a "Study Edition" of The Watchtower that is not distributed to the public. It is used by Jehovah's Witnesses at their weekend meetings.