John Cunningham Mclennan (Oktoba 14, 1867 – Oktoba 9, 1935) alikuwa mwanafizikia wa Kanada. Alizaliwa Ingersoll, Ontario. Alimaliza masomo yake kwenye chuo kikuu cha Toronto mnamo mwaka 1892 na alikuwa profesa wa fizikia huko kutoka mwaka 1907 hadi 1931. Mchango wake mkubwa kwenye fizikia ulikuwa utafiti wake kuhusu ukinzani na upitishaji wa umeme katika vipitishi mbalimbali na spektra za elementi. (yote yanapatikana kwenye archive.org) Note on the temperature variations in the specific resistance of Heusler's alloys (microform), by McTaggart, H. A. (Henry Allen), 1876-1941; McLennan, J. C. (John Cunningham), 1867-1935; Robertson, J. K. (John Kellock), 1885-1958 On the absorption spectra of thallium, aluminium, lead and tin, and arsenic (microform), by McLennan, J. C. (John Cunningham), 1867-1935; Young, J. F. T. (John Francis Todd), 1893-1954; Ireton, H. J. C. (Henry John Cunningham), * On the radioactivity of lead and other metals (microform), by McLennan, J. C. (John Cunningham), 1867-1935;