ADP may refer to:

• Automatic Data Processing, global provider of integrated computing and business outsourcing
• Aéroports de Paris, airport authority for the Parisian region in France
• Aeropuertos del Perú, airport operator for airports in northern Peru
• Alaska Democratic Party, the local branch of the Democratic Party in the state of Alaska
• California Department of Alcohol and Drug Programs, Californian agency dealing with substance abuse prevention and treatment
• Alpha Delta Phi (ΑΔΦ), a fraternal organization on college campuses
• Alpha Delta Pi (ΑΔΠ), a sorority organization on college campuses
• American Democracy Project (AASCU initiative), a project of the AASCU to promote understanding of civic engagement among college students
• American Democracy Project (527 group in Florida)
• Arab Democratic Party (Israel), a former political party in Israel
• Arab Democratic Party (Lebanon), a political party in Lebanon
• Association for the Development of Pakistan, a Boston-based non-profit organization
• Azerbaijan Democratic Party

Alpha Delta Pi (ΑΔΠ) is a Sorority founded on May 15, 1851 at Wesleyan College in Macon, Georgia. The Executive office for this sorority is located on Ponce de Leon Avenue in Atlanta, Georgia. Alpha Delta Pi is one of the two "Macon Magnolias," a term used to celebrate the bonds it shares with Phi Mu. Alpha Delta Pi is the oldest and first secret society for women, and hosts the phrase "first, finest, forever."

Die Abkürzung ADP steht für

ADP peut faire référence à :

• absorption à deux photons, un phénomène physique découvert par Maria Goeppert-Mayer ;
• adénosine diphosphate, un des intermédiaires de la respiration cellulaire en biochimie ;
• Aéroports de Paris, la société gérant les aéroports d'Orly et de Paris-Charles-de-Gaulle.

Adenosindifosfat eller ADP är ett ämne som medverkar i de flesta energiutvinnande processer i ämnesomsättningen. Det fungerar som energibärare när det tillförs en extra fosforgrupp och bildar ATP.

Adenozynodifosforan (adenozyno-5'-difosforan; ADP) - związek organiczny, nukleotyd złożony z rybozy, adeniny i dwóch grup fosforanowych; dołączenie jeszcze jednej grupy powoduje przekształcenie go w ATP, z utworzeniem wysokoenergetycznego wiązania bezwodnikowego. ADP powstaje z ATP w wyniku hydrolizy lub przeniesienia 1 reszty fosforowej z ATP na akceptor (np. glukozę lub białko)