ISTD may refer to:

• Imperial Society of Teachers of Dancing
• In situ thermal desorption (see also Thermal blanket)
• Institute for the Scientific Treatment of Delinquency, now called Centre for Crime and Justice Studies
• International Society of Typographic Designers
• Indian Society for Training and Development

• Merry merry month of May
• Merry Month of May
• Merry Mount
• Merrymount (disambiguation)
• Merrymount, Massachusetts
• Merrymouth
• Merrymouth (band)
• Merry Nickmas
• Merry Riana: Mimpi Sejuta Dolar
• Merry Shannon
• Merrythought cup
• Merryton
• Merryton station
• Merry Trio
• Merryvale, Queensland
• Merryweather helmet
• Merrywidow
• Merry Widow hat
• Merry Widow Waltz
• Merrywing Pond System
• Merry wives of Windsor
• Merrywood Grammar School
• Merry Xmas Everybody: Party Hits
• Merry Xmas From X
• Merry Xmaƨ Everybody