A by-election for the seat of Hartley in the New South Wales Legislative Assembly was held on 14 August 1894 because Joseph Cook had been appointed Postmaster General in the Reid ministry. Such ministerial by-elections were usually uncontested and four ministers were re-elected unopposed, James Brunker (East Maitland), Joseph Carruthers (St George), Jacob Garrard (Sherbrooke) and James Young (The Manning). A poll was required in Bathurst (Sydney Smith), Hartley, Singleton (Albert Gould) and Sydney-King (George Reid) however all were comfortably re-elected.