The youngest child killed in the protests had not yet turned five years old, "a terrible loss", says the UN agency.
Children must be protected at all times. It is everyone's responsibility, says Unicef's spokesperson for South Asia, Sanjay Wijesekera, to BBC.
In one case, a six-year-old girl was shot to death while playing on a rooftop. Dramatic images show how her father tried in vain to protect her from the shooting, writes news agency AP. Most of the 200 people who have died had not themselves participated in the protests.
Since July 15, deadly clashes between police and demonstrators have shaken Bangladesh after large demonstrations against quotas in government services.
The quota system has been reduced by the government, but students have continued to protest - now with demands for justice for those who have died, been injured or imprisoned.
On Friday, demonstrators and police clashed again in large demonstrations in Bangladesh. Two people have died - including one police officer - and over 100 have been injured.
Among other things, the police are said to have fired tear gas, rubber bullets, and stun grenades to disperse stone-throwing demonstrators.
Since the violence broke out on July 15, the authorities have, among other things, shut off the internet and introduced curfews.
