A package substrate may include an insulating substrate, internal circuits and a warpage-suppressing member. The insulating substrate may have a plurality of mount regions in which semiconductor chips may be mounted, and a peripheral region. The internal circuits may be arranged in the mount regions. The warpage-suppressing member is different from the semiconductor chips and may be arranged in at least one of the mount regions to suppress a warpage of the insulating substrate. Thus, warpage of the package substrate may be suppressed during a reflow process.