Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops mostly from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells. Blood, and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leukocytes.

संयोजी ऊतक रेशेदार ऊतक होते हैं। प्राणियों के संयोजी उत्तकों का मुख्य घटक कोलेजन (Collagen) नामक प्रोटीन होता है। यह ऊतक मानव शरीर में एक अंग को दूसरे अंग से जोड़ने का कार्य करता है। यह प्रत्येक अंग में पाया जाता है। यह ऊतकों का एक विस्तृत समूह है। संयोजी ऊतकों का विशिष्ट कार्य संयोजन करना, अंगों को आच्छदित करना तथा उन्हें सही स्थान पर रखना है।