Malaysia is officially a Muslim country - the government and its largest Malay community are all Muslims. However, other religious communities are allowed to practice their faiths, without restrictions. You will find plenty of mosques, Buddhist and Hindu temples, and churches of several dominions all over the cities. All the big festivals of each religion are public holidays here, and all are welcome to join in festivities. If you plan on visiting any religious locations, be mindful to cover your upper arms and legs. Most places will offer to provide a sarong, but it's always nicer to go prepared.