Septimus Charles "Sep" Smith (15 March 1912 – 28 July 2006) was an English footballer who played as a creative wing half and originally as an inside forward. Born in Whitburn, County Durham, in 1912, he was the seventh son born in his family, hence the name Septimus.

He is often considered the best all round player in Leicester City's history and is also the club's longest serving player of all-time having been a player at the club for 19 years and 246 days, as well as captaining the club for 13 years (making him by far the club's longest serving captain).

Smith spent his entire career at Leicester, starting in 1929 and ending in 1949. He made 373 competitive appearances for the Foxes, scoring 37 goals. However, he lost seven seasons of his career because of World War II, during which time he made a further 213 appearances and scored 48 goals during regionalised wartime football. Including these wartime appearances, his tally of 586 appearances makes him Leicester's second top appearance maker of all-time behind Graham Cross.

Smith mentored former Leeds United and England manager Don Revie during his time at Leicester. Revie, who dedicated an entire chapter in his autobiography entitled "What I Owe to Sep Smith" claimed "I'm proud now to think of how much time Sep spent passing on his Soccer knowledge to me. He played a big part in my shaping my career." He also referred to Smith as "an extraordinary footballer," saying "he could place the ball within an inch of a man's toe – [and] that when he lobbed the ball to his winger the opposing full back felt the ball graze his hair as he tried to strain his neck that extra inch, like a drowning man trying to lift his head out of the water."

He was the guest of honour at the Leicester's final game at Filbert Street (the club's home for over 110 years) in April 2002 and a suite at Leicester's current home ground The King Power Stadium is named after him in recognition of his service to the club.