The present disclosure relates to a windows and doors assembly having a ventilation function and a horizontal contact function, and more particularly to a horizontal contact windows and doors assembly for crime prevention and security functions by preventing a window from being open even when the window is slightly open and it is possible to ventilate with the outside air. To achieve the objective of the present disclosure, the windows and doors assembly having a ventilation function and a horizontal contact function includes a window frame, and a windowsill in which the window frame is slidably installed, a handle rotatably installed on the window frame, an engagement unit provided on a lateral surface of the window frame, linked to movement of the handle, and moved in upward and downward directions, an engagement guide provided on the windowsill to face the engagement unit and configured to catch or not catch the engagement unit depending on a position of the engagement unit, and a horizontal moving device provided on at least one of a top surface or a bottom surface of the window frame, linked to the handle, and configured to make the window frame horizontally come into contact with the windowsill or to release horizontal contact depending on movement of the handle, and in this case, when a contact state of the window with respect to the windowsill by the horizontal contact device is released while a catching operation between the engagement unit and the engagement guide is performed, it is possible to ventilate through a gap between the window and the windowsill, the window is restrictly moved to form the gap, and the window is prevented from being freely open.