Beckham had 15 assists for the Galaxy, while Henry scored 14 goals for the Red Bulls, as the former European stars both enjoyed great seasons in MLS.
Beckham was one of four players selected from the Galaxy, who also had Landon Donovan, Todd Dunivant and MLS Defender of the Year Omar Gonzalez named to the squad, which honors the top players in the regular season.
Donovan was honored for the fourth straight year and was one of five players previously honored as a Best XI selection. He played just 23 games this season but had 12 goals and three assists.
D.C. United's Dwayne De Rosario was named for a league-record sixth time after he won the MLS Golden Boot with 16 goals, and also had 12 assists.
This year, players, club leaders and media members voted one goalkeeper, three defenders, five midfielders and two forwards to the Best XI.
Also today, MLS announced that Mark Geiger was selected as the 2011 Referee of the Year and Corey Rockwell was named the Assistant Referee of the Year.
Following is the Best XI, by position:
Goalkeeper: Kasey Keller (Seattle Sounders FC).
Defender: Todd Dunivant (LA Galaxy), Omar Gonzalez (LA Galaxy), Jamison Olave (Real Salt Lake).
Midfielder: David Beckham (LA Galaxy), Brad Davis (Houston Dynamo), Dwayne De Rosario (D.C. United), Landon Donovan (LA Galaxy), Brek Shea (FC Dallas).
Forward: Thierry Henry (New York Red Bulls), Chris Wondolowski (San Jose Earthquakes).