Big List Of Last Names Beginning With O

Are you looking for a comprehensive list of last names beginning with “O”?

We’ve used the 2000 and 2010 U.S. Census to compile 367 surnames that start with the letter O and have at least one thousand bearers of the name.

In the table below, you’ll see the total number of bearers for the name in each census.

Can’t Find A Surname That You Know?

If you don’t find a name that you’re interested in, then use our surname ranking tool which doesn’t have the 1,000 threshold that we’ve imposed on this list.

It will show you where your last name ranks in the U.S. census.

You can learn more in our tutorial on how to check how popular or uncommon your last name is.

What’s Going On With Irish Names?

If you’re of Irish heritage, you’ll be familiar with names like O’Brien. These names start with an O, then an apostrophe, and then a capitalized letter.

You may spot a few names in your list where you’d expect this format but you get something like Obrien instead.

This is because the U.S. census removes apostrophes and capitalizes the name e.g. OBRIEN.

As I’m Irish (and an O’Brien), I decided to amend the data and put in what I consider to be the correct spelling. That’s not always obvious, and I may have missed a few.

Index To Other Letters

ABCDEFG
HIJKLMN
OPQRSTU
VWXYZ

Last Names Starting With O

We’ve broken up this lengthy list by the first two letters to make it easier to scroll and scan.

Last names starting with “Oa”

Last Name2000 Census2010 Census
Oakes17,49917,499 
Oakland1,2001,200 
Oakley17,23817,238 
Oakman1,1301,130 
Oaks7,1827,182 
Oates12,20212,202 
Oatman2,1022,102 

Last names starting with “Ob” or “O’B”

Last Name2000 Census2010 Census
Obando3,4043,404 
O’Banion1,9121,912 
O’Bannon2,6752,675 
Ober3,7243,724 
Oberg5,5375,537 
Oberholtzer2,2892,289 
Oberlander2,1942,194 
Oberle2,3712,371 
Oberlin1,7461,746 
Oberman1,1771,177 
Obermeyer1,5391,539 
Oberry1,8291,829 
Oberst1,2981,298 
Obert2,1532,153 
O’Boyle3,2813,281 
Obregon6,1726,172 
O’Brian3,2033,203 
O’Briant1,2881,288 
O’Brien118,557118,557 
O’Bryan6,4086,408 
O’Bryant4,0014,001 
O’Byrne1,1981,198 

Last names starting with “Oc” or “O’C”

Last Name2000 Census2010 Census
O’Callaghan3,0143,014 
Ocampo25,72025,720 
Ocana2,0642,064 
Ocasio9,2939,293 
Occhipinti1,2901,290 
Ocegueda1,9001,900 
Oceguera3,5993,599 
Ochoa78,67778,677 
Ochs5,9015,901 
Ochsner1,8031,803 
Ocker1,1931,193 
Ocon2,3372,337 
O’Connell36,19436,194 
O’Conner3,6113,611 
O’Connor77,92377,923 
Oda1,7651,765 

Last names starting with “Od”

Last Name2000 Census2010 Census
O’Daniel2,7672,767 
Oday3,6883,688 
Oddo2,6632,663 
O’Dea2,9682,968 
Odegaard1,3311,331 
Odegard1,5971,597 
Odell31,34931,349 
Oden8,2408,240 
Odle3,9843,984 
Odom35,02035,020 
Odoms1,2591,259 
O’Donnell43,46043,460 
O’Donoghue2,1112,111 
O’Donovan1,3451,345 
O’Dowd1,8871,887 
O’Driscoll1,5431,543 
Odum4,3814,381 
Odwyer1,4271,427 

Starting with “Oe”

Last Name2000 Census2010 Census
Oehler2,0952,095 
Oestreich2,2122,212 

Starting with “Of” or “O’F”

Last Name2000 Census2010 Census
O’Farrell2,1272,127 
Officer1,3571,357 
Offord1,1741,174 
Offutt2,8962,896 
O’Flaherty1,3011,301 

Starting with “Og” or “O’G”

Last Name2000 Census 2010 Census
Ogan1,376 1,376 
O’Gara1,849 1,849 
Ogata1,402 1,402 
Ogawa1,887 1,887 
Ogburn3,182 3,182 
Ogden18,860 18,860 
Ogg2,572 2,572 
Ogilvie3,418 3,418 
Ogle14,354 14,354 
Ogles1,135 1,135 
Oglesbee1,096 1,096 
Oglesby12,271 12,271 
Ogletree4,519 4,519 
O’Gorman2,397 2,397 
O’Grady7,306 7,306 
Ogren2,190 2,190 

Starting with “Oh” of “O’H”

Last Name2000 Census2010 Census
Oh18,28518,285 
O’Hagan1,9981,998 
Ohair1,0881,088 
O’Halloran3,2893,289 
O’Hanian1,2101,210 
O’Hanlon2,0632,063 
O’Hara21,71021,710 
O’Hare5,1285,128 
O’Hearn2,7282,728 
Ohern1,3391,339 
Ohl2,0162,016 
Ohler2,4202,420 
Ohlson1,6031,603 
Ohm1,8941,894 
Ohman1,9131,913 

Starting with “Oj”

Last Name2000 Census2010 Census
Oja1,0501,050 
Ojeda22,04522,045 

Starting with “Ok” or “O’K”

Last Name2000 Census2010 Census
Okada1,9871,987 
Okafor1,9391,939 
Okamoto2,3732,373 
Okamura1,2541,254 
O’Kane2,6212,621 
O’Keefe17,41417,414 
O’Keeffe2,0432,043 
O’Kelley2,5242,524 
O’Kelly1,5081,508 
Okun1,0281,028 

Starting with “Ol” or “O’L”

Last Name2000 Census2010 Census 
Olague2,8272,827
Olah1,7731,773
Olalde1,9271,927
Olander2,4622,462
O’Laughlin1,6221,622
Olcott1,1841,184
Old1,0351,035
Oldaker1,4281,428
Olden2,0142,014
Oldenburg2,9442,944
Oldfield2,8162,816
Oldham12,92812,928
Olds7,6707,670
Olea4,4474,447
O’Leary22,32922,329
Olejniczak1,2511,251
Olenick1,0461,046
Oler1,1611,161
Oles1,5521,552
Olesen1,9881,988
Oleson3,7343,734
Olguin10,66010,660
Olin4,1634,163
Olinger5,7325,732
Oliphant5,8085,808
Oliva19,51319,513
Olivares23,98223,982
Olivarez9,7209,720
Olivas20,10620,106
Olive5,7125,712
Oliveira19,05519,055
Oliver115,900115,900
Olivera9,1089,108
Oliveras2,5912,591
Oliveri3,3573,357
Oliverio1,6711,671
Olivero1,8421,842
Oliveros4,6244,624
Olivier6,4006,400
Olivieri3,2893,289
Olivo10,48310,483
Oller2,8002,800
Ollie1,2091,209
Ollis2,0162,016
Olmeda2,2982,298
Olmedo5,7685,768
Olmo1,8791,879
Olmos9,8959,895
Olmstead8,0218,021
Olmsted3,1973,197
Olney3,2483,248
O’Loughlin3,1623,162
Olsen59,35659,356
Olson164,035164,035
Olsson2,6152,615
Olszewski5,5545,554
Oltman1,3891,389
Olvera27,55127,551

Starting with “Om”

Last Name2000 Census2010 Census 
O’Malley17,58817,588
Oman3,1983,198
Omar7,6607,660
O’Mara4,7924,792
O’Meara4,8014,801
Omer2,0632,063

Starting with “On”

Last Name2000 Census2010 Census 
On1,3091,309
Onate1,8381,838
O’Neal47,97947,979
O’Neil28,94928,949
O’Neill50,02850,028
Oney3,5283,528
Ong9,5849,584
Onken1,2211,221
Ono2,1432,143
Onofre3,0993,099
Onorato1,9131,913
Onstott1,1131,113
Ontiveros16,38216,382

Starting with “Op”

Last Name2000 Census2010 Census 
Opitz1,5571,557
Opp1,6591,659
Oppenheim1,7951,795
Oppenheimer2,1822,182
Opperman2,6312,631
Oquendo5,4555,455

Starting with “O’Q”

Last Name2000 Census2010 Census 
O’Quinn5,4395,439

Starting with “Or” or “O’R”

Last Name2000 Census2010 Census 
Oram1,8151,815
Orange4,3504,350
Orantes2,5072,507
Orban1,4851,485
Orchard2,3402,340
Orcutt4,8314,831
Ordaz7,7537,753
Ordonez18,49818,498
Orduna2,4352,435
Orduno2,3472,347
Ordway2,7412,741
Ore1,8621,862
Orear2,1882,188
O’Reilly12,07412,074
Orellana26,65126,651
Orem1,0791,079
Oren1,7661,766
Orenstein1,3701,370
Orf1,2491,249
Organ2,4312,431
Orgeron1,3881,388
Orlandi1,0721,072
Orlando12,58612,586
Orloff1,2591,259
Orlowski3,2083,208
Orman3,1393,139
Orme2,4892,489
Ormiston1,0151,015
Ormond2,3462,346
Ormsby3,6433,643
Orndorff3,1453,145
Ornelas22,96922,969
Orner1,6641,664
Orona6,1456,145
Oropeza7,0827,082
Oros2,5122,512
Orosco8,3138,313
Orosz1,5021,502
O’Rourke16,45716,457
Orozco65,90465,904
Orr44,38844,388
Orrell1,7791,779
Orrick1,3531,353
Orris1,9091,909
Orsi1,1001,100
Orsini3,0553,055
Orso1,1421,142
Ort1,9461,946
Orta7,8207,820
Ortega127,256127,256
Ortego2,6792,679
Ortegon2,1662,166
Ortez3,7623,762
Orth6,3456,345
Ortis1,5841,584
Ortiz286,899286,899
Ortman2,4752,475
Ortner1,3351,335
Orton6,7206,720
Ortuno2,0582,058
Orvis1,7621,762
Orwig1,5851,585
Orzechowski1,5941,594

Starting with “Os”

Last Name2000 Census2010 Census 
Osborn32,43932,439
Osborne66,82766,827
Osbourn1,1401,140
Osbourne2,5632,563
Osburn7,5497,549
Osby1,5731,573
Oscar1,7811,781
Osegueda1,3821,382
Oseguera4,4704,470
Oser1,1341,134
Osgood6,1866,186
O’Shaughnessy3,2463,246
O’Shea10,53110,531
O’Shields1,4981,498
Oshiro3,1773,177
Osinski1,1591,159
Osman9,9089,908
Osmond1,3671,367
Osorio29,48229,482
Osornio2,1692,169
Osowski1,5331,533
Ospina3,7743,774
Ost1,1811,181
Osteen5,4975,497
Ostendorf1,7721,772
Oster6,2596,259
Osterberg1,5271,527
Osterhout2,2882,288
Osterman3,2563,256
Ostler2,1282,128
Ostlund1,4181,418
Ostrander9,5189,518
Ostrom3,4853,485
Ostrow1,2111,211
Ostrowski7,0057,005
Osullivan11,81811,818
Osuna7,6017,601
Oswald14,32214,322
Oswalt5,1985,198

Starting with “Ot”

Last Name2000 Census2010 Census 
Ota1,9841,984
Otero20,93720,937
Otey2,2342,234
Otis7,5497,549
O’Toole10,84210,842
Ott25,73825,738
Otte4,3874,387
Otten4,3964,396
Otter1,3311,331
Otterson1,2261,226
Ottinger3,1123,112
Ottley1,4401,440
Ottman1,5491,549
Otto22,55822,558
Otts1,2681,268
Otwell1,6611,661

Starting with “Ou”

Last Name2000 Census2010 Census 
Ou4,1964,196
Oubre2,0192,019
Ouellette13,98413,984
Ouimet1,2181,218
Ouk1,4241,424
Ours1,5851,585
Ousley4,7514,751
Outen1,3271,327
Outland1,8771,877
Outlaw8,9018,901
Outten1,4011,401
Ouyang1,9681,968
Ouzts1,3741,374

Starting with “Ov”

Last Name2000 Census2010 Census 
Ovalle7,6987,698
Ovalles1,5611,561
Over1,0441,044
Overall1,6441,644
Overbay1,6131,613
Overbeck1,6561,656
Overbey2,6882,688
Overby6,3116,311
Overcash2,6412,641
Overfield1,3701,370
Overholser1,1841,184
Overholt2,8942,894
Overland1,1051,105
Overly2,2012,201
Overman5,3965,396
Overmyer2,1062,106
Overstreet12,34212,342
Overton18,82018,820
Overturf2,2082,208
Oviatt1,2931,293
Oviedo8,1458,145

Starting with “Ow”

Last Name2000 Census2010 Census 
Owen61,63061,630
Owenby2,2412,241
Owens182,719182,719
Owensby2,4202,420
Owings4,3814,381
Ownbey1,1951,195
Ownby2,0262,026
Owsley2,9322,932
Owusu2,9382,938

Starting with “Ox”

Last Name2000 Census2010 Census 
Oxendine7,1397,139
Oxford4,5094,509
Oxley4,3154,315

Starting with “Oy”

Last Name2000 Census2010 Census 
Oyer2,3132,313
Oyler3,4933,493
Oyola2,0512,051

Starting with “Oz”

Last Name2000 Census2010 Census 
Ozment1,3981,398
Ozuna6,3276,327

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