Triplex‐forming peptide nucleic acids (TFPNAs) were targeted to double‐helical regions of 19F‐labeled RNA hairpin models (a UA‐rich duplex with a hexaethylene glycol (heg) loop and a microRNA model, miR‐215). In addition to conventional UV‐ and circular dichroism (CD)‐based detection, binding was monitored by 19F NMR spectroscopy. Detailed information on the stoichiometry and transition between the triple‐helical peptide nucleic acid (PNA)/RNA and (PNA)2/RNA binding modes could be obtained. γ‐(R)‐Hydroxymethyl‐modified thymine‐1‐yl‐ and 2‐aminopyridin‐3‐yl‐acetyl derivatives of TFPNAs were additionally synthesized, which were targeted to the same RNA models, and the effect of the γ‐(R)‐hydroxymethyl group on binding was studied. An appropriate pattern of γ‐(R)‐hydroxymethyl modifications reduced the stability of the ternary complex and preferred stoichiometric binding to the miR‐215 model.