Many countries in the world have moved away from the traditional monarchy; however there are still some countries that do have a king or queen as head of state. Below is a list of many of these countries (although I can't guarantee I've got them all).
H.M Queen Elizabeth II - United Kingdom
H.M King Harald V - Norway
H.M Queen Margrethe II - Denmark
H.M King Juan Carlos I - Spain
H.M King Carl XVI Gustof - Sweden
H.M Queen Beatrix - Netherlands
H.M King Albert - Belgium
H.S.H Prince Albert II - Monaco
H.R.H Grand Duke Henri - Luxembourg
H.M King Addullah bin Abdul Aziz Al-Saud - Saudi Arabi
H.M King Abdullah II - Jordan
H.M King Hamad bin I Sa Al-Khalifa - Bahrain
H.H Shieck Hamad bin Khalifa Al-Thani - Qatar
H.M Sultan Qaboos bin Said Al-Said - Oman
H.H Sheikh Khalifa bin Zayed bin Sulton Al Nahayon - United Arab Emirates (UAE)
H.H Sheikh Humaid bin Rastid Al Nuaim - (UAE)
H.H Sheikh Humaid bin Mohammad Al Sharqi - (UAE)
H.H. Sultan bin Mohammed Al Qasimi - (UAE)
H.H Sheikh Sabah IV Al-Ahmad Al-Jaber Al-Sabah - Kuwait
H.M King Mswati III - Switzerland
H.M King Bhamibol Adulyadej - Thailand
H.M King Jigme Singye Wangchuk - Bhutan
H.M Sultan Haji Hassanal Bolkiah Muizzaddin - Brunei
H.I.M Emporer Akihito - Japan
H.M Norodam Sihamoni - Cambodia
H.M King Mohammed VI - Morocco
OK, so I've had a good go but I still think there are some that I can't find. As far as I am aware there are 44 countries in the world still ruled by kings and queens; 16 of these however, are part of the Commonwealth and so have Queen Elizabeth II as their head of State. Hope this helps!
H.M Queen Elizabeth II - United Kingdom
H.M King Harald V - Norway
H.M Queen Margrethe II - Denmark
H.M King Juan Carlos I - Spain
H.M King Carl XVI Gustof - Sweden
H.M Queen Beatrix - Netherlands
H.M King Albert - Belgium
H.S.H Prince Albert II - Monaco
H.R.H Grand Duke Henri - Luxembourg
H.M King Addullah bin Abdul Aziz Al-Saud - Saudi Arabi
H.M King Abdullah II - Jordan
H.M King Hamad bin I Sa Al-Khalifa - Bahrain
H.H Shieck Hamad bin Khalifa Al-Thani - Qatar
H.M Sultan Qaboos bin Said Al-Said - Oman
H.H Sheikh Khalifa bin Zayed bin Sulton Al Nahayon - United Arab Emirates (UAE)
H.H Sheikh Humaid bin Rastid Al Nuaim - (UAE)
H.H Sheikh Humaid bin Mohammad Al Sharqi - (UAE)
H.H. Sultan bin Mohammed Al Qasimi - (UAE)
H.H Sheikh Sabah IV Al-Ahmad Al-Jaber Al-Sabah - Kuwait
H.M King Mswati III - Switzerland
H.M King Bhamibol Adulyadej - Thailand
H.M King Jigme Singye Wangchuk - Bhutan
H.M Sultan Haji Hassanal Bolkiah Muizzaddin - Brunei
H.I.M Emporer Akihito - Japan
H.M Norodam Sihamoni - Cambodia
H.M King Mohammed VI - Morocco
OK, so I've had a good go but I still think there are some that I can't find. As far as I am aware there are 44 countries in the world still ruled by kings and queens; 16 of these however, are part of the Commonwealth and so have Queen Elizabeth II as their head of State. Hope this helps!