Dave, Davey or David O'Brien may refer to:

Sportsmen

• Davey O'Brien (1917–1977), American football quarterback
• Dave O'Brien (athletic director) (1956–2014), American collegiate professor at Long Beach, Temple and Northeastern
• David O'Brien (racehorse trainer), Irish racehorse trainer during 1970s and 1980s
• Dave O'Brien (sportscaster) (born 1963), American sportscaster
• David O'Brien (sailor) (born 1965), Irish yacht racer in 2000 Summer Olympics
• David O'Brien (swimmer) (born 1983), English freestyle in 2004 Summer Olympics
• David O'Brien (footballer) (born 1984), Scottish left-sided midfielder
• Dave O'Brien (American football), American football player

Others

• Dave O'Brien (actor) (1912–1969), American film and TV performer, director and writer
• David Wright O'Brien (1918–1944), American fantasy and science fiction writer
• David O'Brien (actor) (1937–1989), American performer in daytime dramas
• David P. O'Brien, Canadian business executive since 1980s
• David O'Brien (politician) (born 1970), Australian politician from Victoria

David O'Brien (Politician)