The 1970s formal dress, party dress or prom dress went through several changes during the decade. At first, the short shift cocktail party dress or according pleated swing dress continued its trend from the 60s.

The new dress style was the long empire waist maxi dresses made of flowing chiffon, florals or bold hippie prints topped with bat sleeves or an oversized sheer cape. These morphed into the granny dress or peasant dress, popular as ’70s prom dresses, with a throwback style to the turn of the century late Victorian fashion. Lace insets, ruffle trim, and long bell sleeves embellished these long ’70s party dresses.

At the very end of the ’70s came the era of slinky disco dressed inspired by Gracian draping and simple ballet dance skirts. Metallic colors in liquid fabrics made them sparkle like a disco ball. Don’t forget jumpsuits were also worn as evening and formalwear.

The ’70s are back… or at least a modern interpretation of the decade. ’70s evening dresses in shimmering fabrics, maxi lengths, floral prints, bell sleeves and cape layers are easy to find in regular, petite and plus sizes.  (via Vintage Dancer)

Take a look at these cool pics to see portraits of couples in their prom outfits from the 1970s.