SQLmastar:
Tell him please.
Do unto others what you would that they do unto you.
If you were a boss, would you be glad if your employee works for another?

If the employee is just an employee and not a spouse, why should I have issues with them working for another? Employers abroad allow it so far it doesn't come in the way of the employee carrying out their responsiblity, but in my motherland where paying peanuts and overworking employees is the norm, employers of labour see it as a taboo because it will mean the employees earn more.

Harnny:
Your boss probably maintains 3 jobs

Hahahaha. Very necessary in this Nigerian economy; even 5 jobs self to buffer Buhari economic effect.

I wouldn't tell him if it's not affecting the job adversely.
As long as you are meeting up with your allotted work, then no wahala.

Better, keep it to yourself. It depends on the boss. Your colleagues can mess things up for you if you let them know out of envy.

Don't dare. Its a capitalist world. The same way your boss would look out for himself and his balance sheet first- with or without u, is the same way you should look out for your own bank account. 9 out of 10 bosses would not be cool with it ( including you, if u were the boss).

No one can slave for two masters...

A second job is another job. Kindly resign from the former otherwise you may lose the two jobs in time.

Kelechi009:
He is lying, no one in Nigeria maintains one job.

Keep shut and learn from people's experiences..
I know a very closed person to me who worked for 2 Telecom companies here in Nigeria.

Empress2014:
I think this would depend on your location, in the western world, you would have to declare for some tax reasons I think, In Nigeria, not necessarily especially if one doesn't affect the other.

Declare to the agency in charge of tax, for instance the IRS, but not necessarily to either of your employers.

boolet:

Declare to the agency in charge of tax, for instance the IRS, but not necessarily to either of your employers.

In some EU countries, your employer take care of the taxes, excluding when you want to claim tax refund. When filling a job contract form or signing, the question would even be asked to declare if you have any other job including minijobs

Empress2014:
In some EU countries, your employer take care of the taxes, excluding when you want to claim tax refund. When filling a job contract form or signing, the question would even be asked to declare if you have any other job including minijobs

Makes sense