Kathleen O'Connell (5 October 1888 – 7 April 1956) was an Irish republican activist and Éamon de Valera's personal secretary.

She returned to Ireland briefly in 1915 to attend the Gaelic League oireachtas and ard fheis, voting in favour of the politicisation of the organisation.

[1][2] Éamon de Valera requested that O'Connell join his "consular staff" on 2 October 1919, to support his tour of America.

She joined de Valera and her sister Teresa in Suffolk Street in June 1922 when the Irish Civil War broke out.

[1] When fighting ended in Dublin in July 1922, she traveled south, working closely with Dorothy Macardle, Robert Brennan, and Erskine Childers establishing a publicity department and publishing Poblacht na hÉireann.

[2] O'Connell was present at the first meeting of the provisional organising committee of de Valera's new political party, Fianna Fáil.

She resigned from her permanent civil service position of personal secretary to the Taoiseach when de Valera was defeated in 1948, returning in 1951 when he regained power.

During the writing of their biography of de Valera, Lord Longford and Thomas P. O'Neill used her papers, which are held in the University College Dublin archives, extensively.