Walter Darby Bannard (born September 23, 1934 in New Haven, CT), also known as Darby Bannard, is an American abstract painter.

Bannard attended Phillips Exeter Academy and Princeton University, where he struck up a friendship and working relationship with Frank Stella, which continued after graduation and eventuated in the extreme minimalism both artists engaged in around 1959 and thereafter. The first paintings from the 1959-1965 period contained few forms, as little as a single band painted around a field of color, and then developed into somewhat more complex geometric forms by the mid-60s. In the late 60s the forms dissolved into pale, atmospheric fields of color applied with rollers and paint-soaked rags. He was associated with Lyrical Abstraction, Minimalism, Formalism (art), Post-painterly Abstraction and Color Field painting.

He began using the new acrylic mediums in 1970 and his paintings evolved into colorful expanses of richly colored gels and polymers applied with squeegees and commercial floor brooms, which continues to the present.