This is an incomplete list of lakes in Ontario, a province of Canada. Ontario contains more than 250,000 lakes (including those forming part of the Great Lakes). The Great Lakes are a large binational system shared between Canada and the United States, which hold roughly 20% of the world’s fresh surface water; this figure reflects the volume of the Great Lakes as a whole, not the many smaller lakes across Ontario.
Larger lake statistics
thumb|Ontario relief map
thumb|Lake Superior at Neys Provincial Park Ontario
thumb|Lake Huron
thumb|Frozen Lake Erie
thumb|Looking east across Lake Ontario to [[Toronto]]
thumb|Scarborough bluffs Lake Ontario
thumb|Lake Nipigon
thumb|Rainy Lake from Tango Channel
This is a list of lakes of Ontario with an area larger than .
{| class="wikitable"
<caption>Ontario lakes larger than </caption>
|-
!Lake
!Area (including islands)
!Altitude
!Depth max.
!Volume
|-
|Lake Superior
- Lake 226
- Lake 227
A
B
C
D
E
F
G
H
I
J
K
L
M
thumb|[[Mazinaw Lake]]
N
O
- Oak Lake
- Oba Lake - North
- Oba Lake - South
- Octopus Lake
- Odessa Lake
- Lake Ogoki
- Old Man's Lake
- Onaman Lake
- Lake One
- Onigam Lake
- Onion Lake
- Lake Ontario
- Opeongo Lake
- Opinicon Lake
- Lac Orignal
- Otter Tail Lake
- Ottertooth Lake
- Otty Lake
- Ozhiski Lake
P
- Packsack Lake
- Lake Panache
- Paint Lake
- Pakeshkag Lake
- Papineau Lake
- Lac Paradis
- Paudash Lake
- Peninsula Lake
- Perch Lake
- Pelican Lake
- Percy Lake
- Peters Lake (Sudbury District)
- Pierce Lake
- Pierre Lake
- Pike Lake
- Pigeon Lake
- Lac Pivabiska
- Lake Placid
- Lac à la Plonge
- Pog Lake
- Pokei Lake
- Lac Pomerleau
- Portage Lake
- Pot Lake
- Priamo Lake
- Professor's Lake
- Pumphouse Lake
- Puslinch Lake
- Pine Lake
R
- Rainbow Lake
- Rainy Lake
- Lake Ramsey
- Lac Rancourt
- Rebecca Lake, multiple lakes
- Redbridge Lake
- Red Cedar Lake
- Red Squirrel Lake
- Redstone Lake (Haliburton County)
- Redstone Lake (Sudbury District)
- Restoule Lake
- Rice Lake
- Ril Lake
- Riley Lake (Kenora District)
- Riley Lake (Muskoka)
- Lac du Rocher-Fendu
- Rock Lake (Algonquin Park)
- Rock Lake (Kenora District)
- Lake Rosalind
- Lake Rosseau
- Round Lake
- Ruth Lake
S
- Lac aux Sables
- Sachigo Lake
- Saint Francis (Lac Saint-François)
- Salerno Lake
- Salmon Lake
- Sand Lake, numerous lakes by this name
- Sand Pits Lake
- Sandy Lake (Algoma District)
- Sandy Lake
- Saskatchewan Lake
- Savant Lake
- Sawyer lake
- Lake Scugog
- Lake Seneca
- Seseganaga Lake
- Lac Seul
- Severn Lake
- Seymour Lake (disambiguation), several lakes by this name
- Sharbot Lake
- Shibogama Lake
- Shoal Lake
- Shutze Lake
- Silver Lake (Manitoulin Island)
- Lake Simcoe
- Six Mile Lake
- Skeleton Lake
- Skootamatta Lake
- Loch Smith
- Smoke Lake (Algonquin)
- Smoothrock Lake
- Snider Lake
- Soap Lake
- South Summit Lake
- Sparrow Lake
- Spotter Lake
- Spring Lake
- Lake St. Anthony
- Lake St. Clair
- Lake Ste. Marie
- Lac Ste.-Thérèse
- Steel Lake
- Steve Lake
- Lake St. Francis
- Lake St. George
- Lac St. Jean
- Lake St. John
- St. Joe Lake
- Lake St. Joseph
- Lake St. Lawrence
- Stoco Lake
- Lake St. Patrick
- Lake St. Peter
- Stony Lake
- Sturgeon Lake
- Sunfish Lake
- Lake Superior
- Sydenham Lake
- Syrette Lake
T
- Lake Talon
- Tangamong Lake
- Lake Temagami
- Tetapaga Lake
- Tetu Lake
- The Third Lake
- Thirty Island Lake
- Lake Timiskaming
- Lac Tonnerre
- Lake Travers
- Triangle Lake (Ontario)
- Trout Lake (Algoma District)
- Trout Lake (Nipissing District)
- Tunnel Lake
- Turtle Lake
- Twelve Mile Lake (Ontario)
- Lake Twentythree
- Twin Narrows Lake
- Two Islands Lake
- Twoline Lake
- Lake of Two Mountains
- Lake of Two Rivers
U
- Ulster Lake (Kenora District)
- Upper Algocen Lake
- Upper Beverley Lake
- Upper Nishin Lake
- Upper Redwater Lake
- Upper Rideau Lake
- Umfreville Lake
V
- Lake la Vase
- Lake Vernon
- Lac Viau
- Lake Victoria
W
- Wabatongushi Lake
- Wabigoon Lake
- Lake Wabukayne
- Wahwashkesh Lake
- Wanapitei Lake
- Wapikopa Lake
- Wawa Lake
- Weagamow Lake
- West Shining Tree Lake
- Whiddon Lake
- Lake Whittaker
- White Lake
- Whiteclay Lake
- White Otter Lake
- Whitewater Lake
- Widdifield Lake
- Willard Lake
- Windermere Lake
- Wintering Lake
- Windigo Lake
- Windy Lake
- Winisk Lake
- Wolfe Lake
- Lake Wolsey
- Wood Lake
- Lake of the Woods (Kenora District)
- Lake of the Woods (Manitoulin District)
- Wunnummin Lake
Y
- Yorkend Lake
Z
- Lac de Zajac
- Zionz Lake