O.A. overprinted on stamps of South Australia

South Australia - official stamps - Official Assignee - 1868-1874

OAXACA

Mexico - Oaxaco

O.B. overprinted on stamps of Philippines

Philippines - official stamp - "official business"

OBOCK overprinted on stamps of French Colonies

Somali Coast - (Djibouti)

OBOCK overprinted on stamps of French Colonies

Obock - 1892

OCCUPATION FRANCAISE overprinted on stamps of Hungary

Hungary - French occupation

OCCUPATION FRANCAISE DU CAMEROUN overprinted on stamps of Middle Congo

Cameroun - French administration

OCCUPAZIONE ITALIANA CASTELROSSO

Castellorizo - Italian administration - 1923

OCEANIE

French Polynesia

OESTER POST

Austria

OESTERREICHISCHE and STEMPELMARKE

Austria - revenue stamp

OEUVRES COLONIALES

French Colonies - World War 2 issue - issued by Vichy government in France - ???? - all French Colonies ???

OEUVRES COLONIALES overprinted on stamps of Niger

Niger - World War 2 issue - issued by Vichy Government in France

OEUVRES COLONIALES overprinted on stamps of New Caledonia

New Caledonia - World War 2 issue - issued by Vichy Government in France

OF CASTELLORISO overprinted on stamps of France

Castellorizo - 1920

OFFENTLIG SAK

Norway - official Stamp

OFFICIAL overprinted on stamps of Jamaica

Jamaica - official stamp

OFFICIAL overprinted on stamps of Tanzania

Tanzania - official stamp

OFFICIAL overprinted on stamps of Costa Rica

Costa Rica - official stamp - 1883-1885,1889,1892,1901-1903,1908,1917

OFFICIAL

Peru - official stamp

OFFICIAL overprinted on stamps of Basutoland

Basutoland - official stamp

OFFICIAL overprinted on stamps of Trinidad

Trinidad - official stamp

OFFICIAL overprinted on stamps of South Africa

South Africa - official stamp

OFFICIAL overprinted on stamps of Kenya, Uganda and Tanzania

Tanganyika - official stamp

OFFICIAL overprinted on stamps of Kenya

Kenya - official stamp

OFFICIAL overprinted on stamps of Philippines

Philippines - official stamp

OFFICIAL overprinted on stamps of Liberia

Liberia - official stamp

OFFICIAL overprinted on stamps of New Zealand

New Zealand - official stamp

OFFICIAL overprinted on stamps of Iraq

Iraq - official stamp

OFFICIAL overprinted on stamps of Brazil

Brazil - official stamp

OFFICIAL overprinted on stamps of British Guiana

British Guiana - official stamp

OFFICIAL overprinted on stamps of Trinidad and Tobago

Trinidad and Tobago - official stamp

OFFICIAL 15-VI-1917 overprinted on stamps of Costa Rica

Costa Rica - official stamp - 1917

OFFICIAL and EGYPT

Egypt - official stamp

OFFICIALLY SEALED CANADA DEAD LETTER OFFICE

Canada - official seal

OFFICIALLY SEALED NEWFOUNDLAND DEAD LETTER OFFICE

Canada - official seal

OFFICIAL MAIL USA

United States of America - official mail stamp

OFFICIAL and TCHAD

Chad - official stamps

OFFICIEL overprinted on stamps of Luxembourg

Luxembourg - official stamps

OFFICIEL overprinted on stamps of Switzerland

Switzerland - official stamps - 1942-1945, 1950

OFFICIEL and REPUBLIQUE DU SENEGAL

Senegal - official stamps - 1966-1983

OFFISIEEL overprinted on stamps of South West Africa

South West Africa - official stamp - 1927-1952

OFFISIEEL overprinted on stamps of South Africa

South Africa - official stamp

OFFISIEEL S.W.A. overprinted on stamps of South West Africa

South West Africa - official stamp - 1929

OFF SAK

Norway - official stamps

OFICIAL overprinted on stamps of Nicaragua

Nicaragua - official stamps

OFICIAL overprinted on stamps of Natal

Natal - official stamps

OFICIAL overprinted on stamps of Spain

Spain - official stamps

OFICIAL overprinted on stamps of Paraguay

Paraguay - official stamps

OFICIAL overprinted on stamps of Mexico

Mexico - official stamp

OFICIAL overprinted on stamps of Libya

Libya - official stamps

OFICIAL overprinted on stamps of Honduras

Honduras - official stamps

OFICIAL overprinted on stamps of Guatemala

Guatemala - official stamps

OFICIAL overprinted on stamps of El Salvador

El Salvador - official stamps

OFICIAL overprinted on stamps of Ecuador

Ecuador - official stamps

OFICIAL overprinted on stamps of Costa Rica

Costa Rica - official stamp

OFICIAL overprinted on stamps of Colombia

Colombia - official stamp

OFICIAL overprinted on stamps of Argentina

Argentina - official stamps

OFICIAL overprinted on stamps of Uruguay

Uruguay - official stamps

OFICIAL overprinted on stamps of Chile

Chile - official stamp

OFICIAL and ARGENTINA

Argentina - official stamps

OFICIAL B overprinted on stamps of Nicaragua

Nicaragua - Zelaya province issue

OFICIAL and CHILE

Chile - official stamp

OFICIAL and EL SALVADOR

El Salvador - official stamps

OFICIAL and GUATAMELA

Guatemala - official stamps - 'official' is a perfin

OFICIAL and HONDURAS

Honduras - official stamps

OFICIAL and NICARAGUA

Nicaragua - official stamps

OFICIAL and PARAGUAY

Paraguay - official stamps

OFICIAL and VENEZUELA

Venezuela - official stamps

OFTERREICH overprinted on stamps of Germany

Austria

OHEMS overprinted on stamps of Egypt

Egypt - official stamp - 1922-1923 - 'OHEMS' - 'On His Exhaulted Majesty's Service''

OHHS overprinted on stamps of Egypt

Egypt - official stamp - 1907-1922 - 'OHHS' - 'On His Highness's Service'

OHMS overprinted on stamps of Cook Islands

Cook Islands - official stamp - 'OHMS' - 'On His Majesty's Service'

OHMS overprinted on stamps of Niue

Niue - official stamp - 'OHMS' - 'On His Majesty's Service'

OHMS overprinted on stamps of Canada

Canada - official stamp - 'OHMS' - 'On His Majesty's Service'

OHMS overprinted on stamps of Montserrat

Montserrat - official stamp - 'OHMS' - 'On His Majesty's Service'

OHMS overprinted on stamps of Penrhyn Island

Penrhyn Island - official stamp - 'OHMS' - 'On His Majesty's Service'

OHMS overprinted on stamps of Egypt

Egypt - official stamp - 'OHMS' - 'On His Majesty's Service'

OHMS overprinted on stamps of Aitutaki

Aitutaki - official stamp - 'OHMS' - 'On His Majesty's Service'

OIL RIVERS overprinted on stamps of Great Britain

Niger Coast Protectorate

OKCA

Russia - Army of the North - 1919

OLD GLORY and USA G FIRST CLASS PRESORT

United States of America - nondenomiated stamp/no value indicated - 1994 - 25 cent face value - rate for presorted first class mail - "Old Glory" is a nickname for the USA flag

OLD GLORY and USA G FOR U.S. ADDRESSES ONLY

United States of America - nondenomiated stamp/no value indicated - 1994 - 32 cent face value - rate for first class domestic postage - "Old Glory" is a nickname for the USA flag

OLD GLORY and USA G NONPROFIT PRESORT

United States of America - nondenomiated stamp/no value indicated - 1995 - 5 cent face value - rate for nonprofit (usually a charity) organization's mail - "Old Glory" is a nickname for the USA flag

OLD GLORY and USA G POSTCARD RATE

United States of America - nondenomiated stamp/no value indicated - 1994 - 20 cent face value - rate for postcards - "Old Glory" is a nickname for the USA flag

OLSZTYN ALLENSTEIN and PLEBISCITE overprinted on stamps of Germany

Allenstein - 1920

OLTRE GIUBA overprinted on stamps of Italy

Oltre Giuba - 1925-1926

OLTRE GIVBA

Oltre Giuba

O.M.F. CILICIE overprinted on stamps of France

Cilicia - French administration - "Occupation Militaire Francaise" - "French Military Occupation"

O.M.F. SYRIE overprinted on stamps of France

Syria - postage due stamp - 1920-1922 - 'OMF' - 'Occupation Militaire Francaise' - 'French Military Occupation'

O.M.F. SYRIE overprinted on stamps of France

Syria - 1920-1923 - 'OMF' - 'Occupation Militaire Francaise' - 'French Military Occupation'

O.M.F. SYRIE CH. TAXE overprinted on stamps of France

Syria - postage due stamp - 1920 - 'OMF' - 'Occupation Militaire Francaise' - 'French Military Occupation'

ON C G S overprinted on stamps of India - Cochin

India - Cochin - official stamp

ONE CENT PERAK overprinted on stamps of Straits Settlements

Malaya - Perak - 1886-1890

ONE NEWSPAPER and ADAMS & CO'S EXPRESS

United States of America - carriers's stamp 1840's - for newspapers - operated in the states of California, Oregon, Washington

ONF CASTELLORIZO overprinted on stamps of French Colonies

Castellorizo - 1920 - 'ONF' - 'Occupation Naval Francaise' - 'French Naval Occupation'

ON H. M. S. overprinted on stamps of India

India - official stamp

ON K D S overprinted on stamps of India - Kishangarh

India - Kishangarh - official stamp

ONORANZE AL DUCE DECLI ABRUZZI overprinted on stamps of Eritrea

Eritrea - 1934

ON SERVICE overprinted on stamps of Ceylon

Ceylon - official stamp

ON S S overprinted on stamps of India - Travancore

India - Travancore-Cochin

ON S. S. S. overprinted on stamps of India - Simoor

India - Simoor - official stamp

ON STATE SERVICE overprinted on stamps of Iraq

Iraq - official stamp

ON STATE SERVICE overprinted on stamps of Sharajah and Dependencies

Sharajah and Dependencies - official stamp

ONTARIO LAW STAMP

Canada - revenue stamp - Ontario, Canada

ONTARIO LUXURY TAX

Canada - revenue stamp - Ontario, Canada

ONTARIO TRANSFERS

Canada - revenue stamp - Ontario, Canada - stock transfer

ONZA and CORREOS

Spain - official stamp - 1850s

ONZAS and CORREOS

Spain - official stamp - 1850s

OPSP overprinted on stamps of New Zealand

New Zealand - official stamp

ORANGE RIVER COLONY overprinted on stamps of Cape of Good Hope

Orange River Colony

ORANJE VRIJ STAAT

Orange River Colony - "Oranje Vrij Staat" is German for "Orange Free State"

ORCHA POSTAGE

India - Orcha

ORCHHA STATE

India - Orcha

ORDINARY overprinted on stamps of Liberia

Liberia - 1897-1901 - official stamps overprinted for regular non-official use

ORE

Denmark - monetary unit (also used in Greenland)

ORE

Norway - monetary unit

ORE

Sweden - monetary unit

ORGANISATION INTERNATIONALE DU TRAVAIL and TERRETOIRE FRANCAIS DES AFARS ET DES ISSAS

Afars and Issas - 1971 - 'Organisation Internationale du Travail' - 'International Labor Organization'

ORGANISATION INTERNATIONAL POUR LES REFUGIES overprinted on stamps of Switzerland

Switzerland - official stamp - international organization for refugees - 1950

ORGANISATION METEOROLOGIQUE MONDIALE and HELVETIA

Switzerland - official stamp - world meteorological organization - 1956-1973

ORGANISATION MONDIALE DE LA PROPERIETE INTELLECTUELLE and HELVETIA

Switzerland - official stamp - world intellectual property organization - 1982-1985

ORGANISATION MONDIALE DE LA SANTE overprinted on stamps of Switzerland

Switzerland - official stamp - world health organization - 1948-1950

ORGANISATION MONDIALE DE LA SANTE and HELVETIA

Switzerland - official stamp - world health organization - 1957-1986

ORO PASTAS and LIETUVA

Lithuania - airmail stamp - 1921-1936

ORTS POST

Switzerland

ORTSPOST POSTLOCALE

Switzerland - Zurich

OS overprinted on stamps of New South Wales

New South Wales - official stamp

OS overprinted on stamps of Papua New Guinea

Papua New Guinea - official stamp

OS overprinted on stamps of Trinidad

Trinidad - official stamp

OS overprinted on stamps of Liberia

Liberia - official stamp

OS overprinted on stamps of South Australia

South Australia - official stamp

OS overprinted on stamps of New Guinea

New Guinea - official stamp

OS overprinted on stamps of Newfoundland

Newfoundland

OS overprinted on stamps of Australia

Australia - official stamp - 'OS' - 'On Service'

O.S. G.R.I. overprinted on stamps of German New Guinea

New Britain - official stamp - Georgius Rex Imperator - 1915

O.S.G.S. overprinted on stamps of Sudan

Sudan - official stamp - 1902-1913

OSTEN overprinted on stamps of Germany

Poland - German occupation stamp - 1939

OSTERREICH overprinted on stamps of Germany

Austria - 1945 issues for Lower Austria, Burgenland, and Vienna

OSTERREICH

Austria

OSTERREICHISCHE POST

Austria

OSTERREICHISCHE POST and PORTO

Austria - postage due stamp

OSTERREICH and PORTO

Austria - postage due stamp

OSTERRPOST

Austria

OSTLAND overprinted on stamps of Germany

Russia - German occupation - 1941

OSTROLEKA and POLSKA POCZTA overprinted on stamps of Germany

Poland - local stamp for Ostroleke, Poland - 1918

OTTAWA CONFERENCE 1932 overprinted on stamps of Canada

Canada - 1932 issue to publicize the 1932 Ottawa Economic Conference

OUBANGUI-CHARI

Ubangi-Shari

OUBANGUI-CHARI overprinted on stamps of Middle Congo

Ubangi-Shari - 1922-1923

OUBANGUI CHARI A.E.F. overprinted on stamps of France

Ubangi-Shari - postage due stamp - 1928

OUBANGUI CHARI AFRIQUE EQUATORIALE FRANCAISE overprinted on stamps of Middle Congo

Ubangi-Shari - 1924-1937? Issues

OUBANGUI-CHARI-TCHAD overprinted on stamps of Middle Congo

Ubangi-Shari - 1915-1921

OVS and RDM

Orange Free State - official stamp - 1896-1899 - "Rijdende Dienst Macht" - "mounted police force"

O.W. OFFICIAL overprinted on stamps of Great Britain

Great Britain - official stamps - Office of Works