TLM full form may refer to:

• Traditional Latin Mass, also known as Tridentine Mass

• Taichung Literature Museum, a museum in Taichung, Taiwan
• Télé Lyon Métropole, TV Channel of Lyon's agglomeration
• Temporal light modulation
• The Leprosy Mission
• Thetis Lake Monster
• Transaction-level modeling
• Transmission-line matrix method
• Transmission line measurement
• Transmission line modelling
• The ICAO airline code for Thai Lion Air
• The Indian Railways station code for Tirusulam railway station, Chennai, Tamil Nadu, India
• Teaching/Learning Materials, also known as Instructional materials
• Tech Lead Manager, in technology companies, a "tech lead" (also known as a lead programmer) or team leader who also has some number of direct reports, as a more traditional manager would.