Spherical 10 nm rhabdophane (LaPO₄·H₂O) particles were made by controlled precipitation in water using lanthanum citrate chelate and phosphoric acid (La‐Cit⁺/H₃PO₄) at a temperature of 30°C. Rod‐shaped 10 nm × 100 nm rhabdophane particles were made by direct precipitation from lanthanum nitrate and phosphoric acid (La(NO₃)₃/H₃PO₄). The lanthanum nitrate to phosphoric acid molar ratios (La:P) were fixed at 1:1 and 1:5 for both methods to study their effect on particle size and shape. The particles were characterized with DTA/TGA, XRD, TEM, SEM, Fourier Transform infrared spectroscopy, and ζ potential measurements. The spherical particle surfaces had absorbed citric acid. The point of zero charge of the rod‐shaped and spherical particles was pH 5.4 and 4.3, respectively. Formation mechanisms for the spherical particles are discussed.