Kostretsy may refer to:

• Kostretsy, Pskov Oblast, a village in Pskov Oblast, Russia
• Kostretsy, Tver Oblast, a village in Tver Oblast, Russia

• Dilts
• Diluca
• Diludia
• Diludia bethia
• Diludia brevimargo
• Diludia chromapteris
• Diludia corallina
• Diludia grandis
• Diludia lanuginosa
• Diludia macromera
• Diludia melanomera
• Diludia natalensis
• Diludia rufescens
• Diludia tranquillaris
• Diludia vates
• Dilukái
• Di lung
• Dilupa Perera
• Dilup Gabadamudalige
• Dilute budgerigar mutation
• Dilute sulfuric acid
• Diluting
• Dilution equation
• Dilution (finance)
• Dilution fridge