Béla I was the king of the Kingdom of Hungary between 1061 and 1063.

Béla was a member of the Árpád dynasty, the third son of Vazul and younger brother of Andrew I of Hungary who was crowned king.

In 1048, Andrew shared power with Béla by conferring to him as apanage one third of Hungary ("tercia pars regni", Ducatus, Nitrian Frontier Duchy), whose capital was Nitra, and which involved the southern Slovakia (Nitrian Principality) and northern eastern historic Hungary (called Bihar, however not identical with the later Bihar). Béla received the title of "duke".

Andrew had his son (and Béla's nephew) Solomon crowned future king in 1057, and in 1059, Béla fled to Poland to his brother-in-law Boleslaus II of Poland, brother of Béla's wife Richeza.

In 1060, Béla returned to Hungary and defeated Andrew I to become the new king. After Béla's death in 1063, Henry installed Solomon as the new king and his male progenies had to flee to Poland again.

Béla's and Richeza's children included:

• Géza, ruled as king 1074-1077
• László (Ladislaus), ruled as king 1077-1095
• Lampert, duke of Nitra 1077-1095
• Illona (Helen), married to the king of Croatia Dmitar Zvonimir (1075-1089)