Should employees speak out if their colleagues are unethical?

I concur with the previous response. "Speaking out" can be risky, but doing nothing can be even riskier. It is dependent on the activity and how it affects the workplace. Dishonesty on your partner is unethical, but it's not something your employer should be concerned about. An employer cannot fire someone for something like this. You should not discuss private matters with an employer, regardless of how you believe their behavior reflects on them. Stealing is unethical, and while it may be considered a personal matter, it is also illegal. Depending on the individual's role, it may be prudent to notify an employer of the possibility of workplace theft. Driving recklessly, even if you're technically under the speed limit, is unethical. In this case, you would have a legitimate concern if an employee was driving in an unsafe manner during work hours or for work purposes. Because the behavior may have negative consequences for the workplace, and they can implement safety precautions (including training), a warning may be well received. It’s unethical to use your position to take advantage over other people. In cases where a person is behaving inappropriately, potentially acting in a way that is detrimental to the business itself, then that workplace has a right to know so they can make things right. In each case, whether you notify an employer is determined by whether there is a risk to the business and whether the business can respond to information you have.