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We study the effect of the rotational transform profile on the L–H confinement transitions in the neutral beam-heated plasmas in the TJ-II stellarator. The rotational transform profile in the vacuum is determined by the external coil currents but is modified by the plasma current, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>I</mi><mi>p</mi></msub></semantics></math></inline-formula>. We find that L–H confinement transitions systematically occur when the configuration and plasma current are such that a low-order rational is placed in the plasma edge region, with a distribution centered around <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>ρ</mi><mo>=</mo><mn>0.8</mn><mo>±</mo><mn>0.05</mn></mrow></semantics></math></inline-formula>. It is suggested that magnetohydrodynamic turbulence plays an important role in triggering the L–H transitions at TJ-II.