Baniajan Union () is a union parishad of Dhanbari Upazila, Tangail District, Bangladesh. It is situated 67 km north of Tangail.
According to Population Census 2011 performed by Bangladesh Bureau of Statistics, The total population of Baniajan union is 17271. There are 4760 households in total.
The literacy rate of Baniajan Union is 41.2% (Male-43.6%, Female-39%).