Which nation is culturally closest to Bosnia and Herzegovina?

[Bornoz]

Yes, even in tourist resorts the local people are very religious, there are so many active mosques that you can't get a good night's sleep because the howling of the muezzin will wake you up and to top it off you can't buy or eat pork or any other 'haram' food. A lot of women dress very modestly and cover their heads in some form.

Sure, it's not Saudi Arabia, but it's still a far cry from a secular country.

Secularism doesn't mean ''lack of Islam'' tho
Local people in Serbia are even more religious. There are so many churches and demolished mosques in there. They can serve you haram food and you may not even know it is haram if you are a Muslim. Other than that you can buy and drink alcohol however you want in Turkey even though it is haram according to Islam. There are plenty of secularists who are covering their head.

You can say that Turkey is getting less secular day by day. It is the truth but Turkey based on secular values as much as any other secular country and it is still secular.

[Gold-Shekel]

I think a lot of people have misconceptions. Just because Bosnians preserve and respect what was built during Ottoman times doesn't mean they're close to Turkey. Bosnians usually respect every step of their History and it is part of their culture, from Bogumils to the recent war, from the Austrian rule to Communism, History has shaped the Bosnian identity and it is surprising, judging by the amount of time the Ottoman empire ruled over Bosnia, that Bosnians didn't adopt the culture more, but then again Communists regulated that.

It's only recently that a wave of neo-Ottomanism has striked SDA and its voters, but even that isn't organic, they're trying to cash-in on Erdogan's popularity, same wit SNSD and Dodik with Putin but at least they aim high, unlike HDZ .