Abstract: The collapsible stroller (10) includes a fixed-width collapsible frame (12), a seat (14) mounted on the frame (12) across the width, front wheels (18,20) mounted to the frame (12), and rear wheels (22, 24) mounted to the frame (12). The frame (12) is movable between an open condition and a collapsed condition wherein the frame is collapsed into a generally planar configuration. Each of the rear wheels (22,24) is mounted to a respective wheel frame (66, 68) that is in turn pivotably mounted to a respective side portion of the collapsible frame (12). In the open position, the wheels (22, 24) are aligned perpendicular to the width of the stroller (10). The diameter of the rear wheel (22, 24) is substantially equal to the fixed width of the frame (12). When the wheel frames (66,68) are pivoted, the wheels moves behind the stroller wherein the wheels are positioned substantially parallel to the folding plane, and also within the peripheral width and height boundaries of the collapsed frame (12).