A gas spring and gas damper assembly (AS1) includes a first end member (300) and a second end member (400) that is spaced from the first end member (300). A flexible spring member (200) is secured between the first (300) and second (400) end members and at least partially defines a spring chamber (202) therebetween. A first damper reservoir (322) has a substantially-fixed volume. An elongated gas damping passage (306) is connected in fluid communication between the spring chamber (202) and the first damper reservoir (322). A suspension system including such a gas spring and gas damper assembly as well as a method of assembly are also included.