This article lists the tributaries of the River Thames from the sea to the source, in England. There are also secondary lists of backwaters of the river itself and the waterways branching off.

Note: the River Medway shares the saline lower Thames Estuary.

The average discharge is taken from the lowest point at which measurements are taken, which may be upstream of the confluence.

This list comprises the principal instances; longest ex-mill races (leats), with own articles are included; the main weirstream/river stream of each Thames lock is omitted and the smallest such associated instances but the Sheepwash Channel is included for its importance in Oxford.

Around his Throne the Sea-born Brothers stood,
That swell with Tributary Urns his Flood.
First the fam'd Authors of his ancient Name,
The winding Isis, and the fruitful Tame:
The Kennet swift, for silver Eels renown'd;
The Loddon slow, with verdant Alders crown'd:
Cole, whose clear Streams his flow'ry Islands lave;
And chalky Wey, that rolls a milky Wave:
The blue, transparent Vandalis appears;
The gulphy Lee his sedgy Tresses rears:
And sullen Mole, that hides his diving Flood;
And silent Darent, stain'd with Danish Blood.

— Alexander Pope, Windsor Forest (lines 335–346)

• Locks and weirs on the River Thames
• Islands in the River Thames