The US-based rights group called on Ban to resist pressure from Israel and the United States to keep the Israeli Defense Forces off the list due to be released next week.
"Secretary-General Ban can strengthen child protection in war by compiling his list based on facts, not political pressure," said Philippe Bolopion, crisis advocacy director at Human Rights Watch.
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Human Rights Watch is also calling for the Palestinian Islamist movement Hamas to be included as well as armed groups in Pakistan, Thailand and India for serious violations including attacks on schools and the recruitment of child soldiers.
The current list has 51 groups including Boko Haram and Islamic State as well as the armed forces from eight countries such as Syria, Yemen, the Democratic Republic of Congo and South Sudan.
The 50-day conflict in Gaza last year killed 539 children, injured 2,956, and most Palestinians are now struggling with trauma and life-long disabilities, according to the UN children's agency, UNICEF.