The effect of the Tb3+–doping content (in the range 0–100mol%) on the structure (using Raman spectroscopy) and photoluminescence (PL) properties of both rhabdophane-type La1-xTbxPO4·nH2O and monazite-type La1-xTbxPO4 single-crystal nanorods was investigated. La1-xTbxPO4·nH2O was directly obtained by microwave-assisted hydrothermal synthesis and La1-xTbxPO4 by calcination of La1-xTbxPO4·nH2O at 700°C in air for 2 h. It was found that the characteristic Raman bands shift to higher wavenumbers and become broader with increasing Tb3+ concentration, which is attributed to attendant unit-cell volume reduction. The PL due to the Tb3+ f-f transitions has been studied with continuous and pulsed excitations. The PL intensity increases with doping and is maximum for La0.80Tb0.20PO4·nH2O and La0.85Tb0.15PO4, i.e., for rhabdophane and monazite-type structures, respectively. A quenching effect is detected for concentrations below x=0.05, but constant efficiency is obtained at higher doping. The calcination increases the efficiency by a factor around 2 due to the combined effects of water molecules and defect elimination. The PL decay curves reveal a long lifetime attributable to single Tb3+ ions which is almost independent of doping for monazite nanorods (5–4.5ms), and a shorter one around 0.2ms most likely due to Tb3+ dimmers.