Ysgol Penllwyn is not affiliated with a particular religion/religious denomination collective worship at the school is broadly of a Christian nature. School assemblies are an important part of the school's ethos, they offer an opportunity to develop a sense of community. Harvest, Christmas, Shrove Tuesday and Easter are occasions celebrated at the school. Parents have the right to withdraw their child from collective worship either in its entirety, or pats of it. Parents can do so by contacting their child's teacher. Alternative provision are made for pupils in these circumstances.
The emphasis of religious education is linked to the children’s own experiences in their everyday lives, emphasising religion’s altruistic and caring aspects. Learning about different religions offers and opportunity to celebrate diversity, to explore social influences and ponder some of life’s big questions.