2015–16 Leyton Orient F.C. season

The 2015–16 Leyton Orient F.C. season was the 117th season in the history of Leyton Orient Football Club, their 100th in the Football League, and the first season of their return to the fourth tier of the English football league system.

Transfers in
Total spending: £20,000

Transfers out
Total income: £25,000

Pre-season friendlies
On 1 June 2015, Leyton Orient announced their first two pre-season friendlies against Braintree Town and Woking. A third friendly against Colchester United was added to the schedule. On 1 July 2015, Leyton Orient announced they will face Huddersfield Town during their stay in Spain. On 8 July 2015, Orient confirmed a friendly away to Bishop's Stortford. On 15 July 2015, Leyton Orient announced they will face Middlesbrough in a behind-closed-doors friendly. On 24 July 2015, O's announced a friendly against Southend United.

League Two
On 17 June 2015, the fixtures for the forthcoming season were announced.

League Cup
On 16 June 2015, the first round draw was made, Leyton Orient were drawn away against Milton Keynes Dons.

Football League Trophy
On 8 August 2015, live on Soccer AM the draw for the first round of the Football League Trophy was drawn by Toni Duggan and Alex Scott. O's will travel to Luton Town.

2015–16 squad statistics

 * colspan="12"|Players who left the club during the season
 * colspan="12"|Players who left the club during the season


 * colspan="12"|Out on Loan
 * colspan="12"|Out on Loan