The Principles which Enter into the Inquiry of the Christian Student, Respecting His Field of Labor: An Address Delivered before the Missionary Fraternity in Phillips Academy.
Andover: The Society, 1834.
Encouragement to Missionary Effort among Mohamedans: A Sermon by the Rev. Horatio Southgate, Jun., Missionary of the Protestant Episcopal Church in the United States of America, to Persia, etc.; to which are annexed an Account of the Meeting held at the Church of the Ascension on the Evening of Easter Sunday, April 3, 1836 with the address Delivered Thereat by the Rev. Mr. Southgate, and His Letter of Instructions.
New York: Protestant Episcopal Press, 1836.
Vindication of the Rev. Horatio Southgate: A Letter to the Members of the Protestant Episcopal Church in the United States from the Rev. Horatio Southgate, Their Missionary at Constantinople.
New-York: Stanford and Swords, 1844.
A Letter to a Friend, in Reply to A Recent Pamphlet, from the Missionaries of the American Board of Commissioners for Foreign Missions, at Constantinople.
New-York: D. Appleton & Co., 1845.
Philadelphia: George S. Appleton, 1845.
The Christian Brotherhood: A Sermon Preached in St. Mark's Church, Philadelphia, before the Society for the Advancement of Christianity in Pennsylvania, on Occasion of Their Anniversary, January 7, 1850.
Philadelphia: King and Baird, 1850.
A Sermon preached at the Consecration of Christ Church Cathedral, Fredericton, N.B., August 31, 1853; by The Right Rev. Horatio Southgate, D.D. Late Missionary Bishop at Constantinople, and Rector of the Church of the Advent, Boston, Mass.
The Work of God and Its Means. A Sermon Preached at the Church of the Advent, Boston, Mass., on the First Sunday in Advent, 1853, Being the Ninth Anniversary of the Foundation of the Parish.
Boston: Dutton and Wentworth, 1853.
Sermon preached on the Second Anniversary of the Holy Guild of the Church of the Advent Boston, Mass. On the First Sunday of Advent, 1854.
Boston: J. Howe, 1855.
The War; Its Origin and Its Consequences, by the Right Rev. Horatio Southgate, Bishop of the Protestant Episcopal Church in the United States.
London: James Madden, 1855.
The General Convention of 1856. A Sermon preached in the Church of the Advent, Boston, on the 9th of November, 1856. Being the 25th Sunday after Trinity, and the 5th Anniversary of the depature into Life Eternal of the Rev. William Croswell, D.D., late Rector of that Church. by the Rt. Rev. Horatio Southgate, Rector. Printed by Request, for Private use only.
Boston: Printed by David Clapp, 1856.
Narrative of a Visit to the Syrian (Jacobite) Church of Mesopotamia with Statements and Reflections upon the Present State of Christianity in Turkey and the Character and Prospects of the Eastern Churches.
New-York: Dana and Co., 1856. [External link]
Christ in His Ordinances. A Sermon, Preached in King's Chapel, Boston, The Sixth Sunday after Trinity, July 11, 1858.
Boston: H. W. Dutton and Son, Printers, 1858.
Subjection to the Powers That Be, a Christian Duty.
A Sermon, Preached in Zion Church, New York, the Fifth Sunday after Easter, May 5, 1861.
New York: Wm. C. Bryant.
Prayer and Thanksgiving for the Nation: Written on the Occasion of the President's Request for Prayer and Thanksgiving, on Sunday, September 11, 1864.
New York: H.A. Oliver, 1864.
The Death of Lincoln, April 15th, 1865. Some of the Religious Lessons Which it Teaches. A Sermon, Preached in Zion Church, New-York, on the First Sunday after Easter, April 23d, 1865.
New-York: J.W. Amerman, printer, 1865.
True Churchmanship, and the Variations from It: A Sermon Preached in Zion Church, New York, on the Second Sunday after the Epiphany, January 14, 1866.
New York: John W. Amerman, 1866.
The Rising Again of the Faithful Departed, and their Mutual Recognition. A Sermon in memory of the Reverend James Murray, formerly Curate of Zion Chapel, New York, and lately Rector of All Saints' Memorial Church, Highlands, New Jersey. Preached, Sexagesima Sunday, February 4, 1872. Printed for Private Circulation.
New York: Union Printing House, 1872.
The Cross above the Crescent: A Romance of Constantinople.
Philadelphia: Lippincott, 1878.
A Discourse, in Memory of the Rev. John Jacob Robertson, D.D. Delivered in Trinity Church, Saugerties, N.Y., on the Eighteenth Sunday after Trinity, October 8, 1882.
New York: E. and J.B. Young and Co., 1882.