List of heads of state 1766

Great Britain and Ireland
- Head of State: King George III. (1760–1801) (1801–1820 King of the United Kingdom, 1760–1806 Elector of Braunschweig-Lüneburg, 1814–1820 King of Hanover)
- Head of Government:
  - Prime Minister Charles Watson-Wentworth, 2nd Marquess of Rockingham (1765–1766, 1782 )
  - Prime Minister William Pitt, 1st Earl of Chatham (1766–1768)

Holy Roman Empire
- King and Emperor : Joseph II. (1765–1790) (1780–1790 King of Bohemia, 1780–1790 Duke of Milan, 1780–1790 Duke of Mantua, 1780–1790 Archduke of Austria, 1780–1790 King of Hungary)
- Electoral College
  - Archbishopric of Cologne
    - Elector : Maximilian Friedrich von Königsegg-Rothenfels (1761–1784) (1762–1784 Bishop of Münster)
  - Archbishopric Mainz
    - Elector : Emmerich Joseph von Breidbach zu Bürresheim (1763–1774) (1768–1774 Bishop of Worms)
  - Archbishopric Trier
    - Elector : Johann Philipp von Walderdorff (1756–1768) (1763–1768 Bishop of Worms)
  - Duchy of Bavaria
    - Elector : Maximilian III. Joseph (1745–1777)
  - Kingdom of Bohemia
    - Queen : Maria Theresa (1740–1780) (1740–1780 Duchess of Milan, 1740–1780 Archduchess of Austria, 1740–1780 Duchess of Parma, 1740–1780 Queen of Hungary)
  - Margraviate of Brandenburg
    - Elector : Friedrich II. (1740–1786) (1740–1786 King of Prussia)
  - Duchy of Brunswick-Lueneburg
    - Elector : George III. (1760–1803) (1760–1801 King of Great Britain and Ireland, 1801–1820 King of the United Kingdom, 1814–1820 King of Hanover)
  - Palatine County near the Rhine
    - Elector : Karl Theodor (1742–1799) (1777–1799 Elector of Bavaria, 1742–1799 Duke of Jülich and Berg)
  - Duchy of Saxony
    - Elector : Friedrich August I (1763–1806) (1806–1827 King of Saxony)
- spiritual imperial princes
  - Hochstift Augsburg
    - Bishop : Joseph Ignaz Philipp of Hessen-Darmstadt (1740–1768)
  - Bamberg Monastery
    - Bishop : Adam Friedrich von Seinsheim (1757–1779) (1755–1779 Bishop of Würzburg)
  - Hochstift Basel
    - Bishop : Simon-Nicolas de Montjoie-Hirsingue (1762–1775)
  - Prince Provost Berchtesgaden
    - Provost : Michael Balthasar von Christalnigg (1752–1768)
  - Brixen monastery
    - Bishop : Leopold von Spaur (1747–1778)
  - Hochstift Chur (territory 1648 federal, bishop imperial class without immediate land)
    - Bishop : Johannes Baptist Anton von Federspiel (1755–1777)
  - Corvey Abbey
    - Abbot : Philipp von Spiegel zum Desenberg (1758–1776)
  - Balleien of the Teutonic Order
    - Grand Master : Karl Alexander of Lorraine (1761–1780)
  - Eichstätt Monastery
    - Bishop : Raymund Anton von Strasoldo (1757–1781)
  - Prince Provost Ellwangen
    - Provost : Anton Ignaz von Fugger-Glött (1756–1787) (1769–1787 Bishop of Regensburg)
  - Hochstift Freising
    - Bishop : Clemens Wenzeslaus of Saxony (1763–1768) (1768–1801 Archbishop of Trier, 1768–1803 Bishop of Augsburg, 1763–1769 Bishop of Regensburg, 1787–1803 Provost of Ellwangen, 1768–1794 Abbot of Prüm)
  - Fulda Abbey
    - Bishop : Heinrich von Bibra (1759–1788)
  - Hildesheim Monastery
    - Bishop : Friedrich Wilhelm von Westphalen (1763–1789) (1782–1789 Bishop of Paderborn)
  - Prince Abbey of Kempten
    - Abbot : Honorius Roth von Schreckenstein (1760–1785)
  - Constance monastery
    - Bishop : Franz Konrad von Rodt (1750–1775)
  - Hochstift Lübeck (1555–1803 Protestant administrators)
    - Bishop : Friedrich August von Schleswig-Holstein-Gottorf (1750–1785) (1773–1774 Count of Oldenburg, 1774–1785 Duke of Oldenburg)
  - Liège Monastery
    - Bishop : Charles Nicolas d'Oultremont (1763–1771)
  - Monastery of Münster
    - Bishop : Maximilian Friedrich von Königsegg-Rothenfels (1762–1784) (1761–1784 Archbishop of Cologne)
  - Hochstift Osnabrück (1662–1802 alternating between Catholic and Lutheran bishops)
    - Bishop : Friedrich August von Hannover and Albany (1764–1802)
  - Paderborn Monastery
    - Bishop : Wilhelm Anton von der Asseburg (1763–1782)
  - Passau bishopric
    - Bishop : Leopold Ernst von Firmian (1763–1783) (1748–1758 Bishop of Trient)
  - Regensburg Monastery
    - Bishop : Clemens Wenzeslaus of Saxony (1763–1769) (1768–1801 Archbishop of Trier, 1768–1803 Bishop of Augsburg, 1763–1768 Bishop of Freising, 1787–1803 Provost of Ellwangen, 1768–1794 Abbot of Prüm)
  - Archbishopric Salzburg
    - Archbishop : Sigismund Christoph von Schrattenbach (1753–1771)
  - Speyer Monastery
    - Bishop : Franz Christoph von Hutten zum Stolzenberg (1743–1770)
  - Stablo-Malmedy Abbey
    - Abbot : Alexandre Delmonte (1753–1766)
    - Abbot: Jacques de Hubin (1766–1786)
  - Strasbourg Monastery
    - Bishop : Louis César Constantin de Rohan-Guéméné (1756–1779)
  - Hochstift Trento
    - Bishop : Cristoforo Sizzo de Noris (1763–1776)
  - Hochstift Worms
    - Bishop : Johann Philipp von Walderdorff (1763–1768) (1756–1768 Archbishop of Trier)
  - Würzburg Monastery
    - Bishop : Adam Friedrich von Seinsheim (1755–1779) (1757–1779 Bishop of Bamberg)
- secular imperial princes
  - Principality of Anhalt
    - Anhalt-Bernburg
      - Prince : Friedrich Albrecht (1765–1796)
    - Principality of Anhalt-Dessau
      - Prince : Leopold III. Friedrich Franz (1751–1817) (1751–1758 under guardianship) (from 1807 duke)
    - Principality of Anhalt-Köthen
      - Prince : Karl Georg Lebrecht (1755–1789)
    - Anhalt-Zerbst
      - Prince : Friedrich August (1747–1793) (1747–1752 under guardianship)
  - Arenberg
    - Duke : Karl Maria Raimund (1754–1778)
  - Margraviate of Baden
    - Baden-Baden
      - Margrave : August Georg Simpert (1761–1771)
    - Baden-Durlach
      - Margrave : Karl Friedrich (1738–1771) (1738–1746 under guardianship) (1771–1803 Margrave of Baden, 1803–1806 Elector of Baden, 1806–1811 Grand Duke)
  - Brandenburg-Ansbach
    - Margrave : Karl Alexander (1757–1791) (1769–1791 Margrave of Brandenburg-Bayreuth)
  - Brandenburg-Bayreuth
    - Margrave : Friedrich Christian (1763–1769)
  - Braunschweig-Wolfenbüttel
    - Duke : Charles I (1735–1780)
  - Hessen-Darmstadt
    - Landgrave : Louis VIII (1739–1768)
  - Hessen-Kassel
    - Landgrave : Friedrich II. (1760–1785)
  - Hohenzollern-Hechingen
    - Prince : Josef Friedrich Wilhelm (1750–1798)
  - Hohenzollern-Sigmaringen
    - Prince : Joseph Friedrich Ernst (1715–1769) (until 1720 under guardianship)
  - Jülich and Berg
    - Duke : Karl Theodor (1742–1799) (1777–1799 Elector of Bavaria, 1742–1799 Elector of the Palatinate, 1742–1799 Duke of Palatinate-Neuburg)
  - Liechtenstein
    - Prince : Josef Wenzel ( 1712–1718 , 1748–1772) (1732–1745 Regent of Liechtenstein)
  - Mecklenburg
    - Mecklenburg-Schwerin
      - Duke : Friedrich (1756–1785)
    - Mecklenburg-Strelitz
      - Duke : Adolf Friedrich IV. (1752–1794)
  - Nassau
    - Ottonian line
      - Nassau-Diez
        Prince : Wilhelm V (1751–1806) (1751–1796 governor of the Netherlands)
    - Walramic line
      - Nassau-Saarbrücken
        Prince : Wilhelm Heinrich (1735–1768) (until 1741 under guardianship)
      - Nassau-Usingen
        Prince : Karl (1718–1775) (until 1733 under guardianship)
      - Nassau-Weilburg
        Prince : Karl Christian (1753–1788)
  - Austria
    - Archduchess : Maria Theresa (1740–1780) (1740–1780 Queen of Bohemia, 1740–1780 Duchess of Milan, 1740–1780 Duchess of Parma, 1740–1780 Queen of Hungary)
  - Pfalz-Neuburg
    - Duke : Karl Theodor (1742–1799) (1742–1777 Elector Palatinate, 1777–1799 Elector Palatinate-Bavaria, 1733–1799 Duke of Palatinate-Sulzbach, 1742–1794 / 99 Duke of Jülich and Berg)
  - Pfalz-Sulzbach
    - Duke : Karl Theodor (1733–1799) (1742–1777 Elector Palatinate, 1777–1799 Elector Palatinate-Bavaria, 1742–1799 Duke of Palatinate-Neuburg, 1742–1794 / 99 Duke of Jülich and Berg)
  - Pfalz-Zweibrücken-Birkenfeld
    - Duke : Christian IV (1735–1775)
  - Duchy of Saxony
    - Saxe-Coburg-Saalfeld
      - Duke : Ernst Friedrich (1764–1800)
    - Saxe-Gotha-Altenburg
      - Duke : Friedrich III. (1732–1772)
    - Saxony-Hildburghausen
      - Duke : Ernst Friedrich III. (1745–1780) (1745–1748 under guardianship)
    - Saxony-Meiningen
      - Duke : Karl (1763–1782) (1763–1775 under guardianship)
      - Duke: Georg I (Sachsen-Meiningen) (1763–1803) (1763–1782 under guardianship)
      - Regent: Charlotte Amalie von Hessen-Philippsthal (1763–1782)
    - Saxe-Weimar-Eisenach
      - Duke : Karl August (1758–1828) (1758–1775 under guardianship, 1815–1828 Grand Duke)
      - Regent: Anna Amalia von Braunschweig-Wolfenbüttel (1759–1775)
  - Schwarzburg-Rudolstadt
    - Prince : Johann Friedrich (1744–1767)
  - Schwarzburg-Sondershausen
    - Prince : Christian Günther III. (1758–1794)
  - Waldeck-Pyrmont
    - Prince : Friedrich Karl August (1763–1805) (1805–1812 Prince of Waldeck)
  - Württemberg
    - Duke : Karl Eugen (1737–1793)
- other imperial estates (selection)
  - lip
    - Lippe-Biesterfeld
      - Count : Friedrich Karl August (1736–1781)
    - Lippe-Detmold
      - Count : Simon August (1734–1782)
    - Lippe-Biesterfeld-Weißenfeld
      - Count : Ferdinand Ludwig (1736–1781)
  - Ortenburg
    - Count : Karl III. (1725–1776) (1725–1739 under guardianship)
  - Reuss
    - Reuss older line
      - Reuss overburden
        Count : Heinrich XI. (1723–1768) (1768–1778 Count of Reuss-Greiz, 1778–1800 Prince of Reuss older line)
      - Reuss undergrowth
        Count : Heinrich III. (1733–1768)
    - Reuss younger line
      - Reuss-Ebersdorf
        Count : Heinrich XXIV. (1747–1779)
      - Reuss-Gera
        Count : Heinrich XXX. (1748–1802)
      - Reuss-Lobenstein
        Count : Heinrich II. (1739–1782)
      - Reuss-Schleiz
        Count : Heinrich XII. (1744–1784)
  - Schaumburg-Lippe
    - Count : Wilhelm (1748–1777)

Italian states
- Genoa
  - Doge : Francesco Maria Della Rovere (1765–1767)
- Papal States
  - Pope : Clement XIII. (1758–1769)
- Milan (1706–1800 to Austria)
  - Duchess : Maria Theresa (1740–1780) (1740–1780 Queen of Bohemia, 1740–1780 Archduchess of Austria, 1740–1780 Duchess of Parma, 1740–1780 Queen of Hungary)
    - Governor : Francesco III. d'Este (1754–1771) (1737–1780 Duke of Modena)
- Massa and Carrara
  - Duchess : Maria Teresa Cybo-Malaspina (1731–1790) (until 1744 under guardianship)
- Modena and Reggio
  - Duke : Francesco III. d'Este (1737–1780) (1754–1771 Governor of Milan)
- Naples (1735–1806 personal union with Sicily)
  - King : Ferdinand VII. (1759–1799, 1799–1806, 1815–1816 ) (until 1767 under guardianship) (1759–1816 King of Sicily, 1816–1825 King of the Two Sicilies)
  - Regency council under Bernardo Tanucci (1759–1767)
- Parma and Piacenza
  - Duchess : Maria Theresa (1740–1780) (1740–1780 Queen of Bohemia, 1740–1780 Duchess of Milan, 1740–1780 Archduchess of Austria, 1740–1780 Queen of Hungary)
- Piombino
  - Prince : Gaetano Boncompagni-Ludovisi (1745–1777)
- Sardinia (since 1720 part of Savoy)
  - King : Karl Emanuel III. (1730–1773) (1720–1730 and 1732–1773 Duke of Savoy)
    - Viceroy : Francesco Luigi Costa della Trinità (1763–1767)
- Savoy
  - Duke : Charles Emanuel III. ( 1720–1730 , 1732–1773) (1730–1773 King of Sardinia)
- Sicily (1735–1806 in personal union with Naples)
  - King : Ferdinand III. (1759–1816) (until 1767 under guardianship) (1759–1799, 1799–1806, 1815–1816 King of Naples, 1816–1825 King of both Sicilies)
  - Regency council under Bernardo Tanucci (1759–1767)
    - Viceroy : Giovanni Fogliani Sforza d'Aragona (1755–1773)
- Tuscany
  - Grand Duke : Leopold I (1765–1790) (1790–1792 Emperor, 1790–1792 King of Bohemia, 1790–1792 Duke of Milan, 1790–1792 Archduke of Austria, 1790–1792 King of Hungary)
- Venice
  - Doge : Alvise Mocenigo IV. (1763–1778)

Khanate of Crimea
- Khan : Selim III. Giray (1765-1767, 1770-1771 )

Courland
- Duke : Ernst Johann von Biron ( 1757–1758 , 1763–1769)

Malta
- Grand Master : Manuel Pinto de Fonseca (1741–1773)

Moldova (under Ottoman rule)
- Prince : Grigore III. Ghica (1764–1767, 1774–1777 ) (1768–1769 Prince of Wallachia)

Monaco
- Prince : Honoré III. (1732–1793)
  - Governor General: Antoine Grimaldi (1732–1784)

Netherlands
- Republic of the Seven United Provinces
  - Inheritance holder : Wilhelm V (1751–1795) (1751–1806 Prince of Nassau-Diez)
- Austrian Netherlands (formally part of the Holy Roman Empire until 1714/95)
  - Governor : Karl Alexander von Lothringen (1744–1780) (1761–1780 Grand Master of the Teutonic Order)

Ottoman Empire
- Sultan : Mustafa III. (1757–1774)

Poland
- King : Stanislaus II August Poniatowski (1764–1795)

Portugal
- King : Joseph I (1750–1777)

Prussia
- King : Friedrich II. (1740–1786) (1740–1786 Elector of Brandenburg)

Russia
- Empress : Catherine II (1762–1796)

Sweden
- King : Adolf Friedrich (1751–1771) (1727–1750 Bishop of Lübeck)

Spain
- King : Charles III. (1759–1788) (1735–1759 King of Naples, 1731–1735 Duke of Parma, 1735–1759 King of Sicily)

Hungary
- Queen : Maria Theresa (1740–1780) (1740–1780 Queen of Bohemia, 1740–1780 Duchess of Milan, 1740–1780 Archduchess of Austria, 1740–1780 Duchess of Parma)

Wallachia (under Ottoman rule)
- Prince : Scarlat Ghica ( 1758–1761 , 1765–1766) (1757–1758 Prince of Moldova)
- Prince: Alexandru Ghica (1766–1768)