The legislature of the southern state of Baden-Wurttemberg, led by a coalition of the Christian Democratic Union and the liberal Free Democrats, voted almost unanimously for the new law on Thursday. It will go into effect this month.
State culture minister Annette Schavan said that because Muslim head covering was "open to interpretation" including a possible espousal of the "Islamist political views" it had no place in the classroom.
Germany's highest tribunal, the constitutional court, ruled in September that Baden-Wurttemberg was wrong to forbid a Muslim female teacher, Fereshta Ludin, from wearing a headscarf in the classroom.
But it said Germany's 16 regional states could legislate to ban religious apparel if it was deemed to unduly influence children.
Six states have now put forward draft laws banning headscarves or other religious symbols in public institutions.
Fereshta Ludin's right to wear a
hijab was upheld last year
The latest came this week when the left-wing government in Berlin agreed on a sweeping ban on religious symbols.
The ban would cover not only Muslim hijabs but also large Christian crosses and Jewish skullcaps and apply to police officers, judges and bailiffs as well as public school teachers.
Muslim groups have fiercely criticised the hijab bans as compromising their freedom of religious expression.
The debate in Germany echoes a similar controversy in neighbouring France in recent months.
The French government announced in January it was planning to introduce a ban on obvious religious symbols including the hijab, large crosses and the Jewish skullcap.