Karlovci can refer to:

• Sremski Karlovci, a town and municipality in Srem, Vojvodina, Serbia
• Novi Karlovci, a village in Srem, Vojvodina, Serbia

• Thalmann algorithm
• Thalmann pioneers
• Thalmus
• Thalner
• Thalomicra
• Thalour du perron
• Thalour du Perron
• Thalpius
• Thalpochares accedens
• Thalpochares aerugo
• Thalpochares calida
• Thalpochares chrysaspis
• Thalpochares concinna
• Thalpochares divisa
• Thalpochares laurea
• Thalpochares leonata
• Thalpochares paula
• Thalpochares phoenissa
• Thalpomys
• Thalpophila
• Thalpophila digna
• Thalpophila (moth)
• Thalpophila rubrescens
• Thalpunoor
• Thalsa'