Do sikhs believe in jins?

Respected Brother/Sister,
Waheguru ji ka Khalsa, Waheguru ji ki Fateh!

According to Encyclopaedia Britannica, jinni (plural jinn), also called genie, Arabic jinnī, in Arabic mythology, a spirit inhabiting the earth but unseen by humans, capable of assuming various forms and exercising extraordinary powers. Belief in jinn was common in pre-Islamic Arabia, where they were thought to inspire poets and soothsayers. Their existence was affirmed in the Qurʾān, and they are conceptualized in Islam as creatures parallel to human beings who are capable of choosing between good and evil and must thus face eventual salvation or damnation. They are beings of smokeless flame by nature, in the same manner in which humans are said to be made of earth, and they cannot be seen by human beings.

In Guru Granth Sahib, the first Guru Person, Guru Nanak Sahib, teaches us in his Salok, at Panna 556, that the persons, who live their life in vices and do not become one with Akalpurakh and Shabad Guru, who are spiritually embodiment of each other, are not human beings, but ‘Jinn’;-

ਸਲੋਕ ਮਃ ੧ ॥ ਕਲੀ ਅੰਦਰਿ ਨਾਨਕਾ ਜਿੰਨਾਂ ਦਾ ਅਉਤਾਰੁ ॥ ਪੁਤੁ ਜਿਨੂਰਾ ਧੀਅ ਜਿੰਨੂਰੀ ਜੋਰੂ ਜਿੰਨਾ ਦਾ ਸਿਕਦਾਰੁ ॥੧॥ {ਪੰਨਾ 556}

ਪਦਅਰਥ: ਜਿੰਨ = ਭੂਤ। ਅਉਤਾਰੁ = ਜਨਮ। ਜਿਨੂਰਾ = ਛੋਟਾ ਜਿੰਨ, ਭੂਤਨਾ। ਜਿੰਨੂਰੀ = ਭੂਤਨੀ।

ਅਰਥ: ਹੇ ਨਾਨਕ! ਕਲਜੁਗ ਵਿਚ (ਵਿਕਾਰੀ ਜੀਵਨ ਵਿਚ) ਰਹਿਣ ਵਾਲੇ (ਮਨੁੱਖ ਨਹੀਂ) ਭੂਤਨੇ ਜੰਮੇ ਹੋਏ ਹਨ, ਪੁਤ੍ਰ ਭੂਤਨਾ, ਧੀ ਭੂਤਨੀ ਤੇ ਇਸਤ੍ਰੀ (ਸਾਰੇ) ਭੂਤਨਿਆਂ ਦੀ ਸਿਰਦਾਰ ਹੈ (ਭਾਵ; ਨਾਮ ਤੋਂ ਸੱਖਣੇ ਸਭ ਜੀਵ ਭੂਤਨੇ ਹਨ) ।੧।

Thus, Sikhism has nothing to do with the mythology of ‘Jinn’ but in Sikhi, Guru Sahib has given an entirely different definition of ‘Jinn’.

Hope it helps. If you have any further questions, please do ask. If you find any deficiencies, please point out the same, for improvement in future.

Regards,
Your Brother