Beuttler & Arnold was an architectural firm in Sioux City, Iowa that designed several works that are listed on the National Register of Historic Places for their architecture.

William Buettler (1883-1963) and Ralph Arnold (1889-1961) both worked for architect Wilfred W. Beach in Sioux City. The two began their partnership in Sioux City in 1912, and dissolved it when the advent of World War II stopped almost all non-military construction.^[1]: 37

Works include:

• Florence Crittenton Home and Maternity Hospital (1913), 1105-1111 28th St. Sioux City, Iowa, NRHP-listed
• Hartington Carnegie Library (1914–15), 106 S Broadway, Hartington, Nebraska^[2][3]
• Trimble Block (1915), 6th & Pierce, Sioux City, Iowa^[3]
• Sachse, Bunn & Company Block (1920; Colonial Revival), 201 S. 5th St., Sioux City, Iowa, a contributing building in the Cherokee Commercial Historic District^{[1]: 50–51}
• Sioux City Masonic Temple (1921–22; Spanish Colonial Revival), NRHP-listed^[4]
• Le Mars Central High School, (1924, 1952 additions; Colonial Revival), 335 1st Ave., SW., Le Mars, Iowa, NRHP-listed^[5]
• First Baptist Church of Vermillion (1925), 101 E. Main St. Vermillion, South Dakota, design of second wing (1925), adding to first wing designed by Wallace LeRoy Dow and built during 1889–90.^[6]
• United States Post Office and Courthouse (1934; Moderne and Art Deco) 316-320 6th St., Sioux City, Iowa, NRHP-listed^[7]

Also the NRHP-listed Milo Public Library, at 4 Pleasant St., Milo, Maine, built in 1922, which has Frederick A. Paterson of Bangor recorded as its architect, is almost identical in design to Beuttler and Arnold's Hartington, Nebraska library. Both appear generally to follow the Type F plan provided by James Bertram's Notes on Library Buildings (1910). The Milo library's building committee inquired about, and may have purchased, Beuttler and Arnold's detailed plans.^{[2]: 2, 3}