En Thangai Kalyani is a 1988 Indian Tamil-language film directed and produced by T. Rajendar.
The film stars Rajendar in the lead role alongside Sudha, with Silambarasan also appearing as Velu, Rajendar's real-life son.
The plot revolves around a man who abandons his wife and daughter to live with his concubine, eventually marrying her without caring for his family. His son Velu harbors deep resentment towards their neglectful father but deeply loves his sister Kalyani.
Kalyani falls in love with her college co-student Kannan against the wishes of her brother and mother. However, Kannan is revealed to be a fraud who exploits people for money. Despite Velu's attempts to warn her, she elopes with him.
The story continues after their marriage, detailing how Kannan mistreats Kalyani. Velu supports his sister and mother, buying everything for her and sending her to college.