In the Canton of Zug, the Cantonal Tax Office (Steuerverwaltung) is where any issues relating to tax should be addressed. The municipalities do not have tax administration offices. Private individuals in the Canton of Zug pay both income tax and a wealth tax.

Exception is made for people with a Permit B, they are charged with taxation at source. The tariffs are progressive. You can find help in calculating the rates of tax on: www.zg.ch/steuerverwaltung/steuerrechner - German

Where private individuals do not pay tax deducted at source, they have to fill in a tax declaration/tax return every year. This is usually sent out in February and it has to be completed and returned to the Tax Office by the end of April. Income from earnings worldwide and assets owned throughout the world have to be disclosed in full. Married couples need fill in only one tax declaration and are taxed jointly.
The Tax Office has set up an electronic aid to tax declaration (eTax.zug) which can be found on: www.zg.ch/steuerverwaltung/eTax.zug - German

Please note: As a rule, correspondence with the Tax Office should be in the official language of German, however, some exceptions can be made in the case of English.

Steuerverwaltung (Tax Office)
Bahnhofstrasse 26
Postfach
6301 Zug
Tel. +41 41 728 26 11
Fax +41 41 728 26 99
internet.stv@zg.ch  

Complete texts relating to tax laws can be found on: http://zg.clex.ch/ (63 - taxes, 632 cantonal and municipal taxes) (German)