The phenotype of a plant can be jointly determined by its genotype, the environmental condition experienced by itself and the environmental condition(s) experienced by its parents. The latter, i.e., the impacts of parental environment conditions on offspring phenotypes, are referred to as parental effects, maternal effects or paternal effects. Because parental effects reflect the response of offspring phenotypes to environment conditions across generations, it is also named transgenerational plasticity. Parental effects may have played an important role in the long-term evolution of plant populations, especially for those with limited sexual reproduction and thus low genetic variation. In this paper, we reviewed the research progresses of parental effects and pointed out the future research directions. We explicitly defined two types of parental effects, i.e., clonal parental effects and sexual parental effects. The former refer to parental effects that are transmitted to offspring through ramets produced by clonal growth and other asexual reproduction, while the latter refer to those that are transmitted to offspring through seeds produced by sexual reproduction. While sexual parental effects have long been recognized, clonal parental effects are called for attention only in recent years. Both sexual and clonal parental effects generally enhance offspring performance, but sometimes also show neutral or even negative effects, in response to abiotic or biotic stresses. For clonal parental effects, a few studies have investigated that the impacts on growth and physiological traits of clonal offspring strongly depend on offspring environment and levels of plants (i.e., an individual offspring or all offspring of a parent); however, such impacts on exclusive life-history traits of clonal offspring, such as clonal growth, clonal integration, clonal plasticity and intraclonal labor division, are still unclear. The potential mechanisms of parental effects are the provisioning mechanism, metabolic regulation mechanism and epigenetic mechanism. In natural conditions, these three mechanisms often jointly act to affect offspring phenotypes, and their effects cannot be strictly separated from each other. Although a large body of studies have examined parental effects at individual level, there are still limited studies at population level and virtually none at community level. As parental effects can influence offspring phenotypes, they can influence their intra- and inter-specific competitive ability, which may further impact population structure and dynamics and community function and stability. Therefore, future studies of parental effects should test the impact of phenotypic differences/diversity induced by parental effects on intra-/inter-specific relationships, population structure and dynamics and community function (e.g., productivity) and stability. The epigenetic mechanism underlying these population- and community-level parental effects should also be explicitly evaluated.