The tits, chickadees, and titmice constitute Paridae, a large family of small passerine birds which occur in the northern hemisphere and Africa. Most were formerly classified in the genus Parus.

These birds are called either "chickadees" (onomatopoeic, derived from their distinctive "chick-a dee dee dee" alarm call) or "titmice" in North America, and just "tits" in the rest of the English-speaking world. The name titmouse is recorded from the 14th century, composed of the Old English name for the bird, mase (Proto-Germanic *maison, German Meise) and tit, denoting something small. The spelling was influenced by mouse in the 16th century. Emigrants to New Zealand presumably identified some of the superficially similar birds of the genus Petroica of the family Petroicidae, the Australian robins, as members of the tit family, giving them the title tomtit although, in fact, they are not related.

These birds are mainly small stocky woodland species with short stout bills. Some have crests. They range in length from 10 to 22 centimetres. They are adaptable birds, with a mixed diet including seeds and insects. Many species will live around human habitation and come readily to bird feeders for nuts or seed, and learn to take other foods.
Titmice are in the genus Baeolophus, consisting of the following species:

Bridled Titmouse Baeolophus wollweberi
Oak Titmouse Baeolophus inornatus
Juniper Titmouse Baeolophus ridgwayi
Tufted Titmouse Baeolophus bicolor
Black-crested Titmouse Baeolophus atricristatus.

All are North American Birds. Photos are presented for those species highlighted in red.

Poecile—formerly included in Parus
Sombre tit Poecile lugubris
Caspian tit Poecile hyrcanus (often included in P. lugubris)
Marsh tit Poecile palustris
Willow tit Poecile montanus
Black-bibbed tit Poecile hypermelaenus
Songar tit Poecile songarus (often included in P. montanus)
Carolina chickadee Poecile carolinensis
Black-capped chickadee Poecile atricapillus
Mountain chickadee Poecile gambeli
Mexican chickadee Poecile sclateri
White-browed tit Poecile superciliosus
Père David's tit Poecile davidi
Grey-headed chickadee Poecile cinctus
Boreal chickadee Poecile hudsonicus
Chestnut-backed chickadee Poecile rufescens
Genus Periparus—formerly included in Parus
Black-breasted tit or rufous-naped tit Periparus rufonuchalis
Rufous-vented tit Periparus rubidiventris
Spot-winged tit or black-crested tit Periparus melanolophus
Coal tit Periparus ater—possibly paraphyletic
Yellow-bellied tit Periparus venustulus—sometimes separated in Pardaliparus
Elegant tit Periparus elegans—probably paraphyletic; sometimes separated in Pardaliparus
Palawan tit Periparus amabilis—sometimes separated in Pardaliparus
Genus Lophophanes—formerly included in Parus
European crested tit Lophophanes cristatus
Grey crested tit Lophophanes dichrous
Genus Parus
White-shouldered black tit Parus guineensis
White-winged black tit Parus leucomelas
Southern black tit Parus niger
Carp's tit Parus carpi
White-bellied tit Parus albiventris
White-backed black tit Parus leuconotus
Dusky tit Parus funereus
Rufous-bellied tit Parus rufiventris
Red-throated tit Parus fringillinus
Stripe-breasted tit Parus fasciiventer
Acacia tit Parus thruppi
Miombo tit Parus griseiventris
Ashy tit Parus cinerascens
Grey tit Parus afer
Great tit Parus major
Japanese tit Parus minor (often included in P. major)
Green-backed tit Parus monticolus
White-naped tit Parus nuchalis
Himalayan black-lored tit Parus xanthogenys—sometimes separated in Macholophus
Indian black-lored tit Parus aplonotus
Yellow-cheeked tit Parus spilonotus
Yellow tit Parus holsti
White-fronted tit Parus semilarvatus
Varied tit Parus varius
Genus Pseudopodoces
Ground tit Pseudopodoces humilis
Genus Cyanistes
Blue tit Cyanistes caeruleus
African blue tit Cyanistes teneriffae (formerly included in C. caeruleus)
Azure tit Cyanistes cyanus
Yellow-breasted tit Cyanistes flavipectus (often included in C. cyanus)
Genus Cephalopyrus
Fire-capped tit Cephalopyrus flammiceps
These two monotypic genera are possibly less close to titmice than are the penduline tits:
Genus Sylviparus
Yellow-browed tit Sylviparus modestus
Genus Melanochlora
Sultan tit Melanochlora sultanea