The Chlorophyta includes unicellular, colonial, multicellular and coenocytic green algae. Most chlorophytes are autotrophs, but heterotrophic species are known (Polytoma, Prototheca etc.). The chlorophytes usually live in water, but some species inhabit on land (soil, bark etc.). Some chloropytes haev symbiotic relationship with lichens, ciliates, hydras etc. Many familiar green algae such as Chlorella, Chlamydomonas, Volvox, Scenedesmus and sea lettuce are included in the Chlorophyta. Chlamydomonas reinhardtii is widely used as a model organism.

Organization are varied, but no chlorophycean algae has high tissue differenciation. Plasmodesmata are found in only some chlorophycean and ulvophycean algae. Cells are naked or covered by organic scales or cell wall. Cell wall is usually composed of cellulose, but other polysaccharides or glycoproteins are main compornents in some groups. cellulose-synthesizing terminal complexes are arranged a few rows. Mitosis is basically closed type. Cytokinesis is basically involved with phycoplasts, but sometimes caused by a simple furrowing. Flagellate cell usually posssesses two or four homodynamic flagella bearing from the anterior top of the cell with a radial symmetrical cell architecture (Tetrapytina). However, early divergent members (traditionally called as prasinophyceaeans) have laterally inserted heterodynamic flagella. The outer dynein arm in a certain doublet (no. 1 doublet) is usually reduced or absent. The chloroplast of flagellate cell usually contains the eyespot composed of (layered) lipoidal droplets. The glycolate pathway is involved withglycol dehydrogenase in a mitochondrion. Asexual reproduction is carried by binary fission, zoosporogenesis, sporogenesis, fragmentation etc. Isogamy, anisogamy and oogamy are found in the Chlorophyta.

Traditionally, the term Chlorophyta was ued for all green algae. However, now this term is used to exclude the green algae related closely to the land plants (e.g. Zygnematophyceae, Charophyceae).