2016–17 Welsh Alliance League

The 2016–17 Welsh Alliance League, known as the Lock Stock Welsh Alliance League for sponsorship reasons, is the 33rd season of the Welsh Alliance League, which consists of two divisions: the third and fourth levels of the Welsh football pyramid.

There are fourteen teams in Division 1 and sixteen teams in Division 2, with the champions of Division 1 promoted to the Cymru Alliance and the bottom team relegated to Division 2. In Division 2, the champions and runners-up are promoted to Division 1.

The season began on 12 August 2016 and concluded on 13 May 2017 with Glantraeth as Division 1 champions and Glan Conwy were relegated to Division 2. In Division 2, Llandudno Albion were champions with Mynydd Llandegai as runners-up. Both teams were promoted to Division 1.

Teams
Trearddur Bay were defending champions from the previous season. Greenfield and Nantlle Vale, who were Division 2 champions and runners-up, respectively from the previous season were promoted to Division 1.

Teams
Greenfield were champions in the previous season and were promoted to Division 1 along with runners-up, Nantlle Vale. They were replaced by Llanfairpwll who were relegated from Division 1.

Gwynedd League champions, Y Felinheli and third place, Cemaes Bay were promoted to Division 2.