Red (Ordo) jedna je stepenica u biološkoj sistematici. Nalazi se između nadreda (superordo) i podreda (subordo).
U botanici naziv reda, ako se temelji na prezimenu, na latinskom završava na -ales. Popis redova živog svijeta
A ordo Abrothallales - Dothideomycetes ordo Acanthobdellida - Clitellata ordo Acanthoecida - Choanoflagellatea ordo Acanthopleuribacterales - Holophagae ordo Acarosporales - Lecanoromycetes ordo Accipitriformes - Aves ordo Acholeplasmatales - Tenericutes ordo Acidilobales - Thermoprotei ordo Acidimicrobiales - Actinobacteria ordo Acidithiobacillales - Gammaproteobacteria ordo Acidobacteriales - Acidobacteria ordo Acipenseriformes - Actinopterygii ordo Acoela - Xenacoelomorpha ordo Aconchulinida - Filosa ordo Acorales - Liliopsida ordo Acritarcha ordo incertae sedis - Acritarcha classis incertae sedis ordo Acrochaetiales - Florideophyceae ordo Acroglissida - Peranemea ordo Acrospermales - Dothideomycetes ordo Acrosymphytales - Florideophyceae ordo Actiniaria - Anthozoa ordo Actinomycetales - Actinobacteria ordo Actinulida - Hydrozoa ordo Adapedonta - Bivalvia ordo Aeromonadales - Gammaproteobacteria ordo Afrosoricida - Mammalia ordo Agaricales - Agaricomycetes ordo Agaricostilbales - Agaricostilbomycetes ordo Agelasida - Demospongiae ordo Agyriales - Lecanoromycetes ordo Ahnfeltiales - Florideophyceae ordo Akentrogonida - Maxillopoda ordo Albuliformes - Actinopterygii ordo Alcyonacea - Anthozoa ordo Alismatales - Liliopsida ordo Alteromonadales - Gammaproteobacteria ordo Amblypygi - Arachnida ordo Amborellales - Magnoliopsida ordo Amiiformes - Actinopterygii ordo Amphidiniales - Dinophyceae ordo Amphidiscosida - Hexactinellida ordo Amphilepidida - Ophiuroidea ordo Amphilinidea - Cestoda ordo Amphinomida - Polychaeta ordo Amphionidacea - Malacostraca ordo Amphipoda - Malacostraca ordo Amphisphaeriales - Sordariomycetes ordo Amplistromatales - Sordariomycetes ordo Amylocorticiales - Agaricomycetes ordo Anaerolineales - Anaerolineae ordo Anaeroplasmatales - Tenericutes ordo Anaspidacea - Malacostraca ordo Anaulales - Mediophyceae ordo Anguilliformes - Actinopterygii ordo Anisonemida - Peranemea ordo Annulatascales - Sordariomycetes ordo Anostraca - Branchiopoda ordo Anseriformes - Aves ordo Anthoathecata - Hydrozoa ordo Antipatharia - Anthozoa ordo Anura - Amphibia ordo Aphelenchida - Secernentea ordo Aphragmophora - Sagittoidea ordo Apiales - Magnoliopsida ordo Aplousobranchia - Ascidiacea ordo Aplysiida - Gastropoda ordo Apochela - Eutardigrada ordo Apodida - Holothuroidea ordo Apodiformes - Aves ordo Apoikiales - Chrysophyceae ordo Apororhynchida - Archiacanthocephala ordo Apterygiformes - Aves ordo Apusomonadida - Apusomonadea ordo Apygophora - Maxillopoda ordo Aquificales - Aquificae ordo Aquifoliales - Magnoliopsida ordo Arachnomycetales - Eurotiomycetes ordo Araeolaimida - Adenophorea ordo Araneae - Arachnida ordo Arbacioida - Echinoidea ordo Arcanodiscales - Coscinodiscophyceae ordo Archaegladiopsidales - Coscinodiscophyceae ordo Archaeoglobales - Archaeoglobi ordo Archaeognatha - Insecta ordo Archaeorhizomycetales - Archaeorhizomycetes ordo Archaeosporales - Glomeromycetes ordo Architaenioglossa - Gastropoda ordo Arcida - Bivalvia ordo Arecales - Liliopsida ordo Arguloida - Maxillopoda ordo Arhynchobdellida - Clitellata ordo Arkhangelskiales - Coccolithophyceae ordo Armatimonadales - Armatimonadia ordo Arthoniales - Arthoniomycetes ordo Arthrotardigrada - Heterotardigrada ordo Artiodactyla - Mammalia ordo Ascaridida - Secernentea ordo Ascoseirales - Phaeophyceae ordo Ascosphaerales - Eurotiomycetes ordo Asellariales - Zygomycota ordo Asparagales - Liliopsida ordo Aspidodiadematoida - Echinoidea ordo Aspidogastrida - Trematoda ordo Aspidosiphoniformes - Phascolosomatidea ordo Asterales - Magnoliopsida ordo Asterinales - Dothideomycetes ordo Asterocladales - Phaeophyceae ordo Asterolamprales - Coscinodiscophyceae ordo Asterotexales - Dothideomycetes ordo Astigmata - Arachnida ordo Astrorhizida - Polythalamea ordo Ateleopodiformes - Actinopterygii ordo Atheliales - Agaricomycetes ordo Atheriniformes - Actinopterygii ordo Atractiellales - Atractiellomycetes ordo Atractophorales - Florideophyceae ordo Aulacoseirales - Coscinodiscophyceae ordo Aulopiformes - Actinopterygii ordo Aurearenales - Phaeothamniophyceae ordo Auriculariales - Agaricomycetes ordo Austrobaileyales - Magnoliopsida
B ordo Axinellida - Demospongiae ordo Bacillales - Bacilli ordo Bacillariales - Bacillariophyceae ordo Bacillariophyta ordo incertae sedis - Bacillariophyta classis incertae sedis ordo Bacteroidales - Bacteroidia ordo Baeomycetales - Lecanoromycetes ordo Baerida - Calcarea ordo Balbianiales - Florideophyceae ordo Balliales - Florideophyceae ordo Bangiales - Bangiophyceae ordo Bangiales - Bangiophyceae ordo Basidiobolales - Zygomycota ordo Bathynellacea - Malacostraca ordo Batistiales - Sordariomycetes ordo Batrachoidiformes - Actinopterygii ordo Batrachospermales - Florideophyceae ordo Bdelloidea - Eurotatoria ordo Bdellovibrionales - Deltaproteobacteria ordo Beloniformes - Actinopterygii ordo Berberidopsidales - Magnoliopsida ordo Beroida - Nuda ordo Beryciformes - Actinopterygii ordo Bezerromycetales - Dothideomycetes ordo Bicoecida - Bikosea ordo Biddulphiales - Mediophyceae ordo Biemnida - Demospongiae ordo Bifidobacteriales - Actinobacteria ordo Bihospitida - Postgaardea ordo Bilinguales - Mediophyceae ordo Bivalvulida - Myxozoa ordo Blastocladiales - Blastocladiomycetes ordo Blastocystida - Blastocystea ordo Blastodiniales - Dinophyceae ordo Blattodea - Insecta ordo Bochusacea - Malacostraca ordo Bodonida - Kinetoplastea ordo Boletales - Agaricomycetes ordo Boliniales - Sordariomycetes ordo Bonnemaisoniales - Florideophyceae ordo Boraginales - Magnoliopsida ordo Bothriocephalidea - Cestoda ordo Bothrioplanida - Platyhelminthes ordo Botrydiales - Xanthophyceae ordo Botryosphaeriales - Dothideomycetes ordo Bourgueticrinida - Crinoidea ordo Brachypoda - Cephalocarida ordo Branchiobdellida - Clitellata ordo Brassicales - Magnoliopsida ordo Briggerales - Mediophyceae ordo Brisingida - Asteroidea ordo Bruniales - Magnoliopsida ordo Bryopsidales - Ulvophyceae ordo Bubarida - Demospongiae ordo Bucerotiformes - Aves ordo Burkholderiales - Betaproteobacteria ordo Bursovaginoidea - Gnathostomulida ordo Buxales - Magnoliopsida
C ordo Calanoida - Hexanauplia ordo Caldilineales - Caldilineae ordo Caldisericales - Caldisericia ordo Callipodida - Diplopoda ordo Calosphaeriales - Sordariomycetes ordo Camallanida - Secernentea ordo Camarodonta - Echinoidea ordo Cambojiida - Tentaculata ordo Campylobacterales - Epsilonproteobacteria ordo Candelariales - Lecanoromycetes ordo Canellales - Magnoliopsida ordo Cantharellales - Agaricomycetes ordo Canuelloida - Hexanauplia ordo Capilloventrida - Clitellata ordo Capnodiales - Dothideomycetes ordo Capparales - Magnoliopsida ordo Caprimulgiformes - Aves ordo Capsalidea - Monogenea ordo Carcharhiniformes - Elasmobranchii ordo Cardiida - Bivalvia ordo Cardiobacteriales - Gammaproteobacteria ordo Carditida - Bivalvia ordo Cariamiformes - Aves ordo Carnivora - Mammalia ordo Carpediemonadida - Carpomonadea ordo Carybdeida - Cubozoa ordo Caryophyllales - Magnoliopsida ordo Caryophyllidea - Cestoda ordo Cassiduloida - Echinoidea ordo Casuariiformes - Aves ordo Catenellopsidales - Florideophyceae ordo Cathetocephalidea - Cestoda ordo Caudata - Amphibia ordo Caulobacterales - Alphaproteobacteria ordo Cavibelonia - Solenogastres ordo Celastrales - Magnoliopsida ordo Cephalaspidea - Gastropoda ordo Cephalobaenida - Maxillopoda ordo Ceraceosorales - Exobasidiomycetes ordo Ceramiales - Florideophyceae ordo Ceratodontiformes - Sarcopterygii ordo Ceratophyllales - Magnoliopsida ordo Cercomonadida - Sarcomonadea ordo Cestida - Tentaculata ordo Cetacea - Mammalia ordo Cetomimiformes - Actinopterygii ordo Chaetocerotales - Mediophyceae ordo Chaetodermatida - Caudofoveata ordo Chaetonotida - Gastrotricha ordo Chaetopeltidales - Chlorophyceae ordo Chaetophorales - Chlorophyceae ordo Chaetosphaeriales - Sordariomycetes ordo Chaetosphaeridiales - Coleochaetophyceae ordo Chaetothyriales - Eurotiomycetes ordo Chamaesiphonales - Cyanophyceae ordo Characiformes - Actinopterygii ordo Charadriiformes - Aves ordo Charales - Charophyceae ordo Charophyceae ordo incertae sedis - Charophyceae ordo Chattonellales - Raphidophyceae ordo Cheilostomatida - Gymnolaemata ordo Chimaericolidea - Monogenea ordo Chimaeriformes - Holocephali ordo Chirodropida - Cubozoa ordo Chiroptera - Mammalia ordo Chitonida - Polyplacophora ordo Chlamydiales - Chlamydiae ordo Chlamydomonadales - Chlorophyceae ordo Chloramoebales - Synurophyceae ordo Chloranthales - Magnoliopsida ordo Chlorarachniales (Chlorachniida) - Chlorarachniophyceae (Chlorarachnea) ordo Chlorellales - Trebouxiophyceae ordo Chlorobiales - Chlorobea ordo Chlorocystidales - Ulvophyceae ordo Chlorodendrales - Chlorodendrophyceae ordo Chloroflexales - Chloroflexia ordo Chlorokybales - Chlorokybophyceae ordo Chlorophyceae incertae sedis - Chlorophyceae ordo Chlorophyta ordo incertae sedis - Chlorophyta classis incertae sedis ordo Chloropicales - Chloropicophyceae ordo Chondrillida - Demospongiae ordo Chondrosiida - Demospongiae ordo Chordales - Phaeophyceae ordo Chordeumatida - Diplopoda ordo Chromatiales - Gammaproteobacteria ordo Chromista ordo incertae sedis - Chromista classis incertae sedis ordo Chromulinales - Chrysophyceae ordo Chroococcales - Cyanophyceae ordo Chrysiogenales - Chrysiogenetes ordo Chrysomeridales - Chrysomerophyceae ordo Chrysoparadoxales - Chrysoparadoxophyceae ordo Chrysophyceae ordo incertae sedis - Chrysophyceae ordo Chthonomonadales - Chthonomonadetes ordo Chytridiales - Chytridiomycetes ordo Ciconiiformes - Aves ordo Cidaroida - Echinoidea ordo Ciliatea ordo incertae sedis - Ciliatea ordo Cingulata - Mammalia ordo Cladophorales - Ulvophyceae ordo Classiculales - Classiculomycetes ordo Clathrinida - Calcarea ordo Clionaida - Demospongiae ordo Clostridiales - Clostridia ordo Clupeiformes - Actinopterygii ordo Clypeasteroida - Echinoidea ordo Coccidiniales - Syndiniophyceae (Syndinea) ordo Coccolithales - Coccolithophyceae ordo Coccolithophyceae incertae sedis - Coccolithophyceae ordo Cocconeidales - Bacillariophyceae ordo Coccosphaerales - Coccolithophyceae ordo Coelacanthiformes - Sarcopterygii ordo Colaconematales - Florideophyceae ordo Coleochaetales - Coleochaetophyceae ordo Coleoptera - Insecta ordo Coliiformes - Aves ordo Collembola - Entognatha ordo Collemopsidiales - Eurotiomycetes ordo Collothecacea - Eurotatoria ordo Colponemida - Colponemea ordo Columbiformes - Aves ordo Comatulida - Crinoidea ordo Commatiida - Raphidophyceae ordo Commelinales - Liliopsida ordo Compsopogonales - Compsopogonophyceae ordo Coniochaetales - Sordariomycetes ordo Conioscyphales - Sordariomycetes ordo Copelata - Appendicularia ordo Coraciiformes - Aves ordo Corallimorpharia - Anthozoa ordo Corallinales - Florideophyceae ordo Corallinophycidae ordo incertae sedis - Florideophyceae ordo Cordanales - Sordariomycetes ordo Corethrales - Coscinodiscophyceae ordo Coriobacteriales - Actinobacteria ordo Cornales - Magnoliopsida ordo Coronatae - Scyphozoa ordo Coronophorales - Sordariomycetes ordo Corticiales - Agaricomycetes ordo Coryneliales - Eurotiomycetes ordo Corynodactylales - Florideophyceae ordo Coscinodiscales - Coscinodiscophyceae ordo Craniida - Craniata ordo Craspedida - Choanoflagellatea ordo Crassiclitellata - Clitellata ordo Craterostigmomorpha - Chilopoda ordo Crocodylia - Reptilia ordo Crossosomatales - Magnoliopsida ordo Cryomonadida - Thecofilosea