ITK may stand for:

• ITK (gene), a mammalian gene encoding IL2-inducible T-cell kinase
• Itk, (a.k.a. IncrTk), a programming language
• Innovation TK Ltd
• Insight Segmentation and Registration Toolkit, an extensible open source image software library
• Kalimantan Institute of Technology (Institut Teknologi Kalimantan), a university in Balikpapan, Indonesia
• Inuit Tapiriit Kanatami, a Canadian organisation representing Inuit