The Appapalli Mosque is located in the eastern part of Kayalpatnam (also spelled kayalpattinam and kayalpattanam sometimes) in the Tuticorin district of Tamil Nadu, South India.

It is one of the oldest mosques in the town - believed to have been constructed in the middle of 17th Century C.E.. The mosque gets its name from the religious scholar Sham Shihabuddin appa - author of several religious texts, who - after his death on 26th September, 1709 C.E. (?) (corresponding to Hijri 1121, Rajab 21) - was buried in the mosque complex. The street also gets its name from the mosque.

The mosque was renovated in the early part of 20th century and several new features were added. However, the older part of the mosque was left more or less intact during the renovation. Of the dozen or so old mosques of Kayalpatnam - dating to a period before 18th century C.E. - Appapalli mosque is last of a handful that survive with extensive old structures still remaining.

The mosque complex houses burial grounds, a large square overlooking the street and plenty of trees. Daily prayers as well as the Tharaweeh prayer during Ramadhan are conducted regularly. Friday Jumma prayers are not held here.

Appapalli Mosque is registered with the Tamil Nadu Wakf Board (G.S. No. 448).