Line 4A (ខ្សែទី៤A) is a route of the Phnom Penh City Bus network in Phnom Penh, Cambodia.

It runs northeast to southwest.

[1] The line is represented in the official Phnom Penh City Bus map by Lavender.

Line 03 Line 4B Line 02 Line 03 Line 4B Line 06 Line 03 Line 4B Line 4B Line 4B Line 4B Line 4B Line 4B Line 09 This line used to be represented by the color Purple but switched to Lavender when Line 09 was added in January 2018.