4T or 4-T may refer to:

Biology and chemistry 4-T-TRIS; see Thiotrisescaline 4-t-butylpyrocatechol; see 4-tert-Butylcatechol 4T-MMDA-2; see MMDA

Locomotives 4T class of locomotive LMS Stanier 2-6-4T (disambiguation) LMS 3-Cylindered Stanier 2-6-4T LMS Fairburn 2-6-4T LMS Fowler 2-6-4T Bristol and Exeter Railway 4-2-4T locomotives LMS/BR Class 4 2-6-4T locomotives BR Standard Class 4 2-6-4T LMS 2-Cylindered Stanier 2-6-4T L&YR Hughes 4-6-4T LMS Stanier Class 2 0-4-4T Highland Railway Drummond 0-6-4T Class Highland Railway Drummond 0-4-4T Class 0-8-4T 2-6-4T; see 2-6-4 0-4-4T; see 0-4-4 4-6-4T; see 4-6-4 0-6-4T; see 0-6-4 2-8-4T; see 2-8-4 2-2-4T; see 2-2-4 2-4-4T; see 2-4-4

Other 4T, alias for Four Tet, musician 4T-GTE, a model of Toyota T engine 4T, a model of LWD Szpak, a Polish utility aircraft Piaggio Zip 4T, an urban scooter 4T, the production code for the 1977 Doctor Who serial The Invisible Enemy Fourth Transformation, 2018 campaign promise by Mexico's president to do away with abuses that plagued that nation 4T, an abbreviation for a four-cycle engine, from the German viertakt

See also The Four T's (disambiguation) T4 (disambiguation) TTTT