Long wavelength (∼1.55 μm) GaxIn1−xAs multiple-quantum-wire (MQWR) lasers have been grown by a single-step molecular beam epitaxy technique. The MQWR heterostructure was fabricated in situ using the strain-induced lateral-layer ordering process. The wire formation was confirmed by cross-sectional transmission electron microscopy and polarized photoluminescence spectroscopy. The 77 K threshold current densities for the MQWR laser diodes with laser cavities along [110] and [1̄10] directions show an anisotropy ratio of ∼10. Lasers with contact stripes aligned perpendicular to the quantum wire direction consistently show a lower threshold current density than those with stripes aligned parallel. The typical threshold current density for the MQWR laser with a stripe perpendicular to the quantum wires is ∼1 kA/cm2 at 300 K.