A multiple panel glazing unit including at least two glass spacer bars (2) of toughened glass each having, optionally, opposite sides that are chamfered towards a common end surface (8) and which are sealed to the glass panels (22, 24) of multiple panel glazing unit by a transparent or translucent sealant (38). The use of toughened glass spacers allows the manufacture of multiple panel glazing units to meet given operating requirements, e.g. the ability to withstand externally applied forces such as varying differential air pressure of a given magnitude across the unit, with a smaller inter-glazing panel spacing than if glass spacers that are not toughened are used.