Thomas William Arnold Thacker, nicknamed Brown Tom, is a Canadian musician. He is the lead guitarist, lead singer and co-founder of the punk rock group Gob, and guitarist, keyboardist and backing vocalist for Sum 41. Thacker formed Gob with Theo Goutzinakis in 1993. Following Dave Baksh's departure from Sum 41 on May 11, 2006, Thacker was recruited as their touring guitarist, and then became an official member in 2009. He has remained with Sum 41 ever since, even after Baksh rejoined the band in 2015, contributing to four studio releases.

Gob is a Canadian punk rock band from Langley, British Columbia, formed in 1993. The band consists of Tom Thacker, Theo Goutzinakis, Gabe Mantle and Steven Fairweather. They were nominated for a Juno Award for best new group in 2000, and received another Juno nomination for best video in 2002. Gob's most successful album is World According to Gob. Their best-selling songs to date are "I Hear You Calling", "Soda", and "Banshee Song". They have been featured in movies, TV shows, and many sporting video games such as NHL 2002, NHL 2003, NHL 2004 and Madden NFL 2004 with songs such as "Oh! Ellin", "I've Been Up These Steps", "Sick With You", "I Hear You Calling" and "Give Up the Grudge". The band has appeared at several music festivals, the most well-known being the Vans Warped Tour. Thacker is also a lead and rhythm guitarist for fellow Canadian rock band Sum 41.