Fuladh ibn Manadhar (Persian: دیر فولاد بن مانا), was a Justanid prince, who served as a high-ranking military officer of the Buyid dynasty.
Fuladh was the son of Manadhar, an Justanid king. Fuladh had a brother named Khusrau Shah, who ruled Rudbar after Manadhar. He also had an unnamed sister, who married the Buyid ruler Adud al-Dawla, and bore him two sons, Abu'l-Husain Ahmad and Abu Tahir Firuzshah. During that period, Fuladh, along with a Gilaki officer named Ziyar ibn Shahrakawayh, dominated the Buyid court of Baghdad. After the death of Adud al-Dawla, the Buyid Empire was thrown into civil war; the Empire was disputed between his two sons Samsam al-Dawla and Sharaf al-Dawla. Samsam al-Dawla ruled Iraq, while Sharaf al-Dawla ruled Fars and Kerman.
In 986, a Daylamite officer named Asfar ibn Kurdawayh rebelled against Samsam al-Dawla, and changed his allegiance to Sharaf al-Dawla. However, Asfar quickly changed his mind, and declared allegiance to the latter's other brother Abu Nasr Firuz Kharshadh, who was shortly given the honorific epithet of "Baha' al-Dawla." However, Samsam al-Dawla, with the aid of Fuladh, suppressed the rebellion, and imprisoned Baha al-Dawla. Samsam al-Dawla shortly made peace with Sharaf al-Dawla, and agreed to release Baha al-Dawla. In 987, Sharaf al-Dawla betrayed Samsam al-Dawla, conquered Iraq, and had him imprisoned in a fortress. He then imprisoned Fuladh and had Ziyar executed.