Speaking to the general public:
Frequently Asked Questions
...
Is there a dress code?
No. However, Jehovah’s Witnesses try to dress modestly and respectfully.
Meanwhile, speaking to members out of the other side of their mouth:
The Governing Body has decided that sisters may choose to wear slacks...they should not be casual, but dignified, modest, and appropriate. When a sister has a part on the program, she should wear a skirt or a dress... In addition, brothers may choose not to wear a tie or a jacket when participating in the ministry and when attending Christian meetings, assemblies, and conventions... When a brother has a part on the program, he should wear a tie and a jacket if that is the standard of dress in that land.