Capital with K

• Kiev

  Yes! Capital of Ukraine (older spelling of Kyiv).

• Kathmandu

  Yes! Capital city of Nepal.

• Kabul

  Yes! Capital city of Afghanistan.

• Kingston

  Yes! Capital of Jamaica (and Norfolk Island).

• Kuala Lumpur

  Yes! National capital of Malaysia.

• Kinshasa

  Yes! Capital city of DR Congo.

• Kampala

  Yes! Capital city of Uganda.

• Kuwait City

  Yes! Capital city of the country Kuwait.

• Kigali

  Yes! Capital city of Rwanda.

• Karachi

  Yes—former capital of Pakistan (till 1959).

• Khartoum

  Yes! Well-known capital of Sudan.

• Kingstown

  Yes! Capital of St. Vincent and the Grenadines.

• Karnataka
• Kanpur
• Kandahar

The words in the list Capital with K come from players of the word game City, Country, River.