An optically-controlled reconfigurable NRI-TL metamaterial phase shifter operating at 3.6 GHz is proposed. A host transmission line with a fixed length loaded with series capacitors and shunt inductors is used to achieve reconfigurability, while the optical control is introduced by integrating highly resistive silicon switches within the shunt branches of the NRI-TL design. The two states of the phase shifter result in a phase shift of ±60° leading to a differential phase shift of 120° with an insertion loss of 1.3 dB and 1.8 dB respectively. The operational bandwidth of the phase shifter is between 3.45-3.75 GHz. The versatile optical control and the high-frequency response make the proposed NRI-TL phase shifter well suited for 5G antenna array applications.