| Inscription | Country | Years | #Issued |
| Kais.Kon.Zeitungs Stempel | Austria (Newspaper) | 1853-90 | 10 |
| Kalayaan Nang Pilipinas | Philippines(isl)(Japanese Occ.) | 1943 | 6 |
| Kamerun | German: Cameroun(aut) | 1897-15 | 70 |
| Karjala | Karelia? | 1922-43 | 40 |
| Karjala(ovpt) | Bogus | ||
| Karki | Turkya: Aegean(isl) | 1912-32 | 26(tot)- |
| Karolinen | Caroline Islands | 1900-19 | 25 |
| Katanga | Katanga (rebelion) | 1960-63 | 20? |
| Katibo | Bogus | ||
| Kaulbach Island | Canada: Kaulbach Island (bogus/local) | 1980s | 50? |
| Kedah | Malaya: Kedah(sta) | 1912- | 140 |
| Kelantan | Malaya: Kelantan(sta) | 1911- | 120 |
| Kenttapostia | Finland (military) | 1941-63 | 8 |
| Kenya | Kenya | 1963- | 450 |
| Kenya & Uganda | Kenya, Uganda & Tanz | 1922-27 | 20 |
| Kenya, Uganda & Tanganyika | Kenya, Uganda & Tanz | 1935-63 | 90 |
| Kenya, Uganda, Tanganyika & Zanzibar | Kenya, Uganda & Tanz | 1964 | 4 |
| Kenya, Uganda & Tanzania | Kenya, Uganda & Tanz | 1965-76 | 180 |
| KGL Post | Denmark | 1851-68 | 20 |
| Kiautschou | Kiauchau | 1900-09 | 40 |
| Kibris | Cyprus | 1962- | |
| Kingdom of Saudi Arabia | Saudi Arabia | 1962-70 | |
| Kionga | Kionga | 1916 | 4 |
| Kionga(ovpt) | Kionga | 1916 | 6? |
| Kiribati | Kiribati | 1979- | 180 |
| Kishangarh | India: Kishangarh(sta) | 1899-1947 | 120 |
| K.K.Osterreichische Post | Austria | 1908-19 | |
| KKPost Stempel | Austria | 1850-54 | 15 |
| KKPost Stempel | Austria: Lombardy-Venetia | 1850 | 5 |
| K.K. Zeitungs Post | Austria (Newspaper) | 1851-63 | 10 |
| Klaipeda | German: Memel(occ/cty) | 1923 | 80 |
| Korea | Korea | 1948-51 | 100 |
| KPHTH | Crete | 1900-10 | 150 |
| Kraljevstvo SHS | Yugoslavia | 1919-20 | 20 |
| K.S.A. | Saudi Arabia | 1975-81 | 150 |
| K-u-K Feldpost | Austria (Military) | 1915-18 | 90 |
| K-u-K Feldpost | Romania (Austrian occ.) | 1917-18 | 35 |
| K-u-K Militarpost | Bosnia & Herzegovina | 1912-18 | |
| Kuwait | Kuwait | 1923-62 | 175 |
| Kuzey Kibris Turk Cumhuryeti | Turkish Northern Cyprus | 1978?- | 200? |
| K.Wurtt Post | Germany: Wurttemberg(sta) | 1875-1919 | 70 |
If there are any missing inscription, tell me : marcosampaio@grupo.bfe.pt
