This study investigated iconicity in sign language with specific reference on the types, nature, and roles of iconicity in Tanzanian Sign Language. The study was conducted in Tanzania Association for the Deaf in Dar es Salaam region and Mwanga School for the Deaf in Kilimanjaro region. The study involved 24 informants and 300 signs which were purposely selected. The data for this study were collected through interview, observation, and introspection and analyzed qualitatively in the form of analogy. The study findings revealed the following: First, there are two types of iconicity rooted on the basis of signs, each type providing different description of a referent. Second, signs are manifested in various forms based on the highlighted features of a referent. Some of the iconic forms are linked to certain categories of signs while others cut across. The findings also demonstrate that a number of traits or characters of the referent are portrayed simultaneously owing to the feature that has been highlighted. Third, the findings reveal that iconicity plays a significant role in the identification of lexical signs as well as in facilitating communication between signers and non-signers. The study therefore concludes that the understanding of iconicity in general, its types, nature, and its roles largely depends on the awareness of the basis of signs. The study recommends further research on iconicity especially iconicity in syntax, and language change.