The seventy-third Oregon Legislative Assembly was the Oregon Legislative Assembly (OLA)'s period from 2005 to 2006. (The Legislative Assembly is the legislative body of the U.S. state of Oregon, composed of the Oregon State Senate and the Oregon House of Representatives.) There was a regular session in 2005, and a one-day special session on April 20, 2006.

The Senate was controlled by the Democratic Party of Oregon during the 73rd legislature, and the House was controlled by the Oregon Republican Party.

The 2005 regular session was the second longest in Oregon history, lasting 208 days, from January until August.

Two members of the House (Dan Doyle, R-Salem and Kelley Wirth, D-Corvallis) resigned due to unrelated scandals in 2005.

Senate President: Peter Courtney (D-11 Salem)
President Pro Tem: Margaret Carter (D-22 Portland)
Majority Leader: Kate Brown (D-21 Portland)
Minority Leader: Ted Ferrioli (R-30 John Day)

Speaker: Karen Minnis (R-49 Wood Village)
Speaker Pro Tempore: Dennis Richardson (R-4 Central Point)
Majority Leader: Wayne Scott (R-39 Oregon City)
Assistant Majority Leader: Debi Farr (R-14 Eugene)
Assistant Majority Leader: Billy Dalto (R-21 Salem)
Majority Whip: Derrick Kitts (R-30 Hillsboro)
Democratic Minority Leader: Jeff Merkley (D-47 Portland)