The ruthenium-catalyzed remote ε-C-H alkylation of phosphines with tertiary alkyl halides has been developed. This novel PIII-directed C-H activation strategy tolerated various functional groups and delivered a wide variety of modified phosphines with excellent meta-site selectivity. Preliminary mechanistic studies indicated that a PIII-assisted ortho-cyclometalation/remote σ-activation pathway might be involved in this methodology.